From 5277cd0f21c6c0c2de31f294c26aaad8832fbbd9 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 10:50:32 +0200
Subject: [PATCH 01/10] fix(eslint): add missing browser globals history and
 location

---
 eslint.config.mjs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/eslint.config.mjs b/eslint.config.mjs
index 5f2f9f5..3eab547 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -37,8 +37,10 @@ export default [
         URL: "readonly",
         URLSearchParams: "readonly",
         WebSocket: "readonly",
+        history: "readonly",
+        location: "readonly",
         self: "readonly",
-        process: "readonly"
+        process: "readonly",
       }
     },
     rules: {

From d38a8401147756f75e2907719afb6147e8820abe Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 12:44:43 +0200
Subject: [PATCH 02/10] refactor(server): extract rate-limiter module from
 index.js

Move 6 rate-limit functions, all rate-limit Maps, cleanup intervals,
and denial counter to server/rate-limiter.js. 149 lines extracted.
Index.js re-exports what tests and ops.js need.
npm run verify passes.
---
 server/index.js        | 198 ++++++++---------------------------------
 server/rate-limiter.js | 163 +++++++++++++++++++++++++++++++++
 2 files changed, 199 insertions(+), 162 deletions(-)
 create mode 100644 server/rate-limiter.js

diff --git a/server/index.js b/server/index.js
index 42e50f1..2cc126d 100644
--- a/server/index.js
+++ b/server/index.js
@@ -12,6 +12,38 @@ import {
     isAdminMetricsAuthorized,
     isAdminMetricsTokenStrong
 } from './ops.js';
+import {
+    ROOM_LIST_COOLDOWN_MS,
+    HEALTH_RATE_LIMIT_PER_MINUTE,
+    ADMIN_METRICS_AUTH_RATE_LIMIT_PER_MINUTE,
+    connectionCounts,
+    failedAuthAttempts,
+    eventCounts,
+    healthCounts,
+    adminMetricsAuthCounts,
+    roomListCooldowns,
+    rateLimitDenied,
+    checkAuthRate,
+    recordAuthFailure,
+    checkConnectionRate,
+    checkEventRate,
+    checkHealthRate,
+    checkAdminMetricsAuthRate,
+    startRateLimitCleanup,
+    stopRateLimitCleanup,
+    clearRateLimitMaps
+} from './rate-limiter.js';
+
+// Re-export for external consumers (tests, ops)
+export {
+    HEALTH_RATE_LIMIT_PER_MINUTE,
+    ADMIN_METRICS_AUTH_RATE_LIMIT_PER_MINUTE,
+    healthCounts,
+    adminMetricsAuthCounts,
+    connectionCounts,
+    eventCounts,
+    rateLimitDenied
+};
 
 dotenv.config();
 
@@ -26,9 +58,6 @@ const MAX_ROOMS = parseInt(process.env.MAX_ROOMS) || 1000;
 const MAX_PEERS_PER_ROOM = parseInt(process.env.MAX_PEERS_PER_ROOM) || 25;
 const MIN_VERSION = process.env.MIN_VERSION || '1.0.0';
 const ADMIN_METRICS_TOKEN = process.env.ADMIN_METRICS_TOKEN || '';
-const ROOM_LIST_COOLDOWN_MS = 10000;
-export const HEALTH_RATE_LIMIT_PER_MINUTE = 10;
-export const ADMIN_METRICS_AUTH_RATE_LIMIT_PER_MINUTE = 5;
 const HEALTH_RESPONSE_CACHE_TTL_MS = 60000;
 
 if (!isAdminMetricsTokenStrong(ADMIN_METRICS_TOKEN)) {
@@ -108,6 +137,8 @@ export const io = new Server(httpServer, {
     allowUpgrades: false
 });
 
+startRateLimitCleanup(io);
+
 /**
  * In-memory storage
  */
@@ -126,157 +157,6 @@ function log(type, message, details = '') {
     console.log(`[${timestamp}] [${type}] ${message}`, details);
 }
 
-// Rate Limiting & Security
-export const connectionCounts = new Map(); // ip -> { count, resetTime }
-const failedAuthAttempts = new Map(); // Map<IP+RoomID, {count, lastAttempt}>
-
-function checkAuthRate(ip, roomId) {
-    const key = `${ip}:${roomId}`;
-    const now = Date.now();
-    const record = failedAuthAttempts.get(key) || { count: 0, lastAttempt: 0 };
-    
-    // Block for 15 mins if 5 fails in 2 mins
-    if (record.count >= 5 && (now - record.lastAttempt) < 15 * 60 * 1000) {
-        return false;
-    }
-    
-    // Reset if last attempt was long ago
-    if ((now - record.lastAttempt) > 2 * 60 * 1000) {
-        record.count = 0;
-    }
-    
-    return true;
-}
-
-function recordAuthFailure(ip, roomId) {
-    if (failedAuthAttempts.size > 200000) {
-        const now = Date.now();
-        // 1. Clear expired entries (> 15 mins)
-        for (const [key, record] of failedAuthAttempts.entries()) {
-            if (now - record.lastAttempt > 15 * 60 * 1000) {
-                failedAuthAttempts.delete(key);
-            } else {
-                break;
-            }
-        }
-        
-        // 2. If still over 200k, perform LRU-style eviction on the oldest 10,000 entries (first items in Map order)
-        if (failedAuthAttempts.size > 200000) {
-            log('SECURITY', 'failedAuthAttempts size exceeded 200000. Performing insertion-order eviction.');
-            for (const [key] of failedAuthAttempts.entries()) {
-                if (failedAuthAttempts.size <= 190000) {
-                    break;
-                }
-                failedAuthAttempts.delete(key);
-            }
-        }
-    }
-    const key = `${ip}:${roomId}`;
-    const record = failedAuthAttempts.get(key) || { count: 0, lastAttempt: 0 };
-    record.count++;
-    record.lastAttempt = Date.now();
-    failedAuthAttempts.delete(key); // Remove first to update insertion order (moves key to the end of iteration)
-    failedAuthAttempts.set(key, record);
-}
-
-// Periodically clean up old auth failure records (every 15 minutes)
-const authFailureCleanupInterval = setInterval(() => {
-    const now = Date.now();
-    for (const [key, record] of failedAuthAttempts.entries()) {
-        if (now - record.lastAttempt > 15 * 60 * 1000) {
-            failedAuthAttempts.delete(key);
-        }
-    }
-}, 15 * 60 * 1000);
-
-export const eventCounts = new Map(); // socketId -> { count, resetTime }
-export const healthCounts = new Map(); // ip -> { count, resetTime }
-export const adminMetricsAuthCounts = new Map(); // ip -> { count, resetTime }
-const roomListCooldowns = new Map(); // socketId -> last allowed timestamp
-
-// Actual rate-limit denial counters (incremented only when a request is denied)
-const rateLimitDenied = {
-    connections: 0,
-    events: 0,
-    health: 0,
-    adminMetricsAuth: 0,
-    roomList: 0
-};
-
-// Clean up connection counts and event counts to prevent memory leak
-const rateLimitCleanupInterval = setInterval(() => {
-    const now = Date.now();
-    for (const [ip, entry] of connectionCounts.entries()) {
-        if (now > entry.resetTime) {
-            connectionCounts.delete(ip);
-        }
-    }
-    for (const [socketId, entry] of eventCounts.entries()) {
-        if (now > entry.resetTime || !io.sockets.sockets.has(socketId)) {
-            eventCounts.delete(socketId);
-        }
-    }
-    for (const [ip, entry] of healthCounts.entries()) {
-        if (now > entry.resetTime) {
-            healthCounts.delete(ip);
-        }
-    }
-    for (const [ip, entry] of adminMetricsAuthCounts.entries()) {
-        if (now > entry.resetTime) {
-            adminMetricsAuthCounts.delete(ip);
-        }
-    }
-    for (const [socketId] of roomListCooldowns.entries()) {
-        if (!io.sockets.sockets.has(socketId)) {
-            roomListCooldowns.delete(socketId);
-        }
-    }
-}, 60000);
-
-function checkConnectionRate(ip) {
-    const now = Date.now();
-    const entry = connectionCounts.get(ip) || { count: 0, resetTime: now + 60000 };
-    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 60000; }
-    entry.count++;
-    connectionCounts.set(ip, entry);
-    if (entry.count <= 10) return true;
-    rateLimitDenied.connections++;
-    return false;
-}
-
-function checkEventRate(socketId) {
-    const now = Date.now();
-    const entry = eventCounts.get(socketId) || { count: 0, resetTime: now + 10000 };
-    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 10000; }
-    entry.count++;
-    eventCounts.set(socketId, entry);
-    if (entry.count <= 30) return true;
-    rateLimitDenied.events++;
-    return false;
-}
-
-function checkHealthRate(ip) {
-    const now = Date.now();
-    const entry = healthCounts.get(ip) || { count: 0, resetTime: now + 60000 };
-    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 60000; }
-    entry.count++;
-    healthCounts.set(ip, entry);
-    if (entry.count <= HEALTH_RATE_LIMIT_PER_MINUTE) return true;
-    rateLimitDenied.health++;
-    return false;
-}
-
-function checkAdminMetricsAuthRate(ip) {
-    const now = Date.now();
-    const entry = adminMetricsAuthCounts.get(ip) || { count: 0, resetTime: now + 60000 };
-    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 60000; }
-    entry.count++;
-    adminMetricsAuthCounts.set(ip, entry);
-    if (entry.count <= ADMIN_METRICS_AUTH_RATE_LIMIT_PER_MINUTE) return true;
-    rateLimitDenied.adminMetricsAuth++;
-    return false;
-}
-
 /**
  * Central peer teardown. Removes a socket from all room state and notifies
  * remaining peers. Call this from every disconnect/leave/reaper/dedupe path.
@@ -836,20 +716,14 @@ function gracefulShutdown(signal) {
 }
 
 export async function stopServerForTests() {
-    clearInterval(authFailureCleanupInterval);
-    clearInterval(rateLimitCleanupInterval);
+    stopRateLimitCleanup();
     clearInterval(roomCleanupInterval);
     rooms.clear();
     socketToRoom.clear();
     peerToSocket.clear();
     roomCreationLocks.clear();
     peerJoinLocks.clear();
-    connectionCounts.clear();
-    failedAuthAttempts.clear();
-    eventCounts.clear();
-    healthCounts.clear();
-    adminMetricsAuthCounts.clear();
-    roomListCooldowns.clear();
+    clearRateLimitMaps();
     healthResponseCache.clear();
     io.removeAllListeners();
     io.disconnectSockets(true);
diff --git a/server/rate-limiter.js b/server/rate-limiter.js
new file mode 100644
index 0000000..fc39891
--- /dev/null
+++ b/server/rate-limiter.js
@@ -0,0 +1,163 @@
+/**
+ * KoalaSync Rate Limiter
+ * Connection, event, health, and auth rate limiting for the relay server.
+ */
+
+export const ROOM_LIST_COOLDOWN_MS = 10000;
+export const HEALTH_RATE_LIMIT_PER_MINUTE = 10;
+export const ADMIN_METRICS_AUTH_RATE_LIMIT_PER_MINUTE = 5;
+
+export const connectionCounts = new Map(); // ip -> { count, resetTime }
+export const failedAuthAttempts = new Map(); // Map<IP+RoomID, {count, lastAttempt}>
+export const eventCounts = new Map(); // socketId -> { count, resetTime }
+export const healthCounts = new Map(); // ip -> { count, resetTime }
+export const adminMetricsAuthCounts = new Map(); // ip -> { count, resetTime }
+export const roomListCooldowns = new Map(); // socketId -> last allowed timestamp
+
+export const rateLimitDenied = {
+    connections: 0,
+    events: 0,
+    health: 0,
+    adminMetricsAuth: 0,
+    roomList: 0
+};
+
+let authCleanupId = null;
+let rateLimitCleanupId = null;
+
+export function checkAuthRate(ip, roomId) {
+    const key = `${ip}:${roomId}`;
+    const now = Date.now();
+    const record = failedAuthAttempts.get(key) || { count: 0, lastAttempt: 0 };
+
+    if (record.count >= 5 && (now - record.lastAttempt) < 15 * 60 * 1000) {
+        return false;
+    }
+
+    if ((now - record.lastAttempt) > 2 * 60 * 1000) {
+        record.count = 0;
+    }
+
+    return true;
+}
+
+export function recordAuthFailure(ip, roomId) {
+    if (failedAuthAttempts.size > 200000) {
+        const now = Date.now();
+        for (const [key, record] of failedAuthAttempts.entries()) {
+            if (now - record.lastAttempt > 15 * 60 * 1000) {
+                failedAuthAttempts.delete(key);
+            } else {
+                break;
+            }
+        }
+
+        if (failedAuthAttempts.size > 200000) {
+            console.warn('SECURITY: failedAuthAttempts size exceeded 200000. Performing insertion-order eviction.');
+            for (const [key] of failedAuthAttempts.entries()) {
+                if (failedAuthAttempts.size <= 190000) {
+                    break;
+                }
+                failedAuthAttempts.delete(key);
+            }
+        }
+    }
+    const key = `${ip}:${roomId}`;
+    const record = failedAuthAttempts.get(key) || { count: 0, lastAttempt: 0 };
+    record.count++;
+    record.lastAttempt = Date.now();
+    failedAuthAttempts.delete(key);
+    failedAuthAttempts.set(key, record);
+}
+
+export function checkConnectionRate(ip) {
+    const now = Date.now();
+    const entry = connectionCounts.get(ip) || { count: 0, resetTime: now + 60000 };
+    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 60000; }
+    entry.count++;
+    connectionCounts.set(ip, entry);
+    if (entry.count <= 10) return true;
+    rateLimitDenied.connections++;
+    return false;
+}
+
+export function checkEventRate(socketId) {
+    const now = Date.now();
+    const entry = eventCounts.get(socketId) || { count: 0, resetTime: now + 10000 };
+    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 10000; }
+    entry.count++;
+    eventCounts.set(socketId, entry);
+    if (entry.count <= 30) return true;
+    rateLimitDenied.events++;
+    return false;
+}
+
+export function checkHealthRate(ip) {
+    const now = Date.now();
+    const entry = healthCounts.get(ip) || { count: 0, resetTime: now + 60000 };
+    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 60000; }
+    entry.count++;
+    healthCounts.set(ip, entry);
+    if (entry.count <= HEALTH_RATE_LIMIT_PER_MINUTE) return true;
+    rateLimitDenied.health++;
+    return false;
+}
+
+export function checkAdminMetricsAuthRate(ip) {
+    const now = Date.now();
+    const entry = adminMetricsAuthCounts.get(ip) || { count: 0, resetTime: now + 60000 };
+    if (now > entry.resetTime) { entry.count = 0; entry.resetTime = now + 60000; }
+    entry.count++;
+    adminMetricsAuthCounts.set(ip, entry);
+    if (entry.count <= ADMIN_METRICS_AUTH_RATE_LIMIT_PER_MINUTE) return true;
+    rateLimitDenied.adminMetricsAuth++;
+    return false;
+}
+
+export function startRateLimitCleanup(io) {
+    // Clean up old auth failure records (every 15 minutes)
+    authCleanupId = setInterval(() => {
+        const now = Date.now();
+        for (const [key, record] of failedAuthAttempts.entries()) {
+            if (now - record.lastAttempt > 15 * 60 * 1000) {
+                failedAuthAttempts.delete(key);
+            }
+        }
+    }, 15 * 60 * 1000);
+
+    // Clean up rate-limit maps to prevent memory leaks (every 60 seconds)
+    rateLimitCleanupId = setInterval(() => {
+        const now = Date.now();
+        for (const [ip, entry] of connectionCounts.entries()) {
+            if (now > entry.resetTime) connectionCounts.delete(ip);
+        }
+        for (const [socketId, entry] of eventCounts.entries()) {
+            if (now > entry.resetTime || !io.sockets.sockets.has(socketId)) {
+                eventCounts.delete(socketId);
+            }
+        }
+        for (const [ip, entry] of healthCounts.entries()) {
+            if (now > entry.resetTime) healthCounts.delete(ip);
+        }
+        for (const [ip, entry] of adminMetricsAuthCounts.entries()) {
+            if (now > entry.resetTime) adminMetricsAuthCounts.delete(ip);
+        }
+        for (const [socketId] of roomListCooldowns.entries()) {
+            if (!io.sockets.sockets.has(socketId)) roomListCooldowns.delete(socketId);
+        }
+    }, 60000);
+}
+
+export function stopRateLimitCleanup() {
+    if (authCleanupId) { clearInterval(authCleanupId); authCleanupId = null; }
+    if (rateLimitCleanupId) { clearInterval(rateLimitCleanupId); rateLimitCleanupId = null; }
+}
+
+export function clearRateLimitMaps() {
+    connectionCounts.clear();
+    failedAuthAttempts.clear();
+    eventCounts.clear();
+    healthCounts.clear();
+    adminMetricsAuthCounts.clear();
+    roomListCooldowns.clear();
+}

From d7bb8dc97c16022039d98433d847efe9b70da52c Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 12:48:11 +0200
Subject: [PATCH 03/10] refactor(extension): extract episode-utils from
 background.js + content.js

Move extractEpisodeId() and sameEpisode() to shared episode-utils.js.
background.js imports via ES module. content.js (IIFE) receives injected
copy via build-extension.js marker replacement, eliminating duplication.
---
 extension/background.js    | 21 ++-------------------
 extension/content.js       | 17 ++++++++---------
 extension/episode-utils.js | 24 ++++++++++++++++++++++++
 scripts/build-extension.js | 19 +++++++++++++++++++
 4 files changed, 53 insertions(+), 28 deletions(-)
 create mode 100644 extension/episode-utils.js

diff --git a/extension/background.js b/extension/background.js
index 9f44a08..44dfe5a 100644
--- a/extension/background.js
+++ b/extension/background.js
@@ -1,6 +1,7 @@
 import { EVENTS, PROTOCOL_VERSION, OFFICIAL_SERVER_URL, OFFICIAL_SERVER_TOKEN, EPISODE_LOBBY_TIMEOUT, FORCE_SYNC_TIMEOUT } from './shared/constants.js';
 import { generateUsername } from './shared/names.js';
 import { loadLocale, getMessage, getSystemLanguage } from './i18n.js';
+import { sameEpisode } from './episode-utils.js';
 
 // --- Uninstall URL Initialization ---
 chrome.runtime.onInstalled.addListener((details) => {
@@ -191,25 +192,7 @@ let forceSyncTimeout = null;
 let episodeLobby = null; // { expectedTitle, initiatorPeerId, readyPeers: [], createdAt }
 let episodeLobbyTimeout = null;
 
-// --- Episode Title Extraction (synced with content.js) ---
-function extractEpisodeId(title) {
-    if (!title || typeof title !== 'string') return null;
-    const se = title.match(/S(?:eason\s*)?(\d+)[\s\-\.]*E(?:pisode\s*)?(\d+)/i);
-    if (se) return `S${String(se[1]).padStart(2, '0')}E${String(se[2]).padStart(2, '0')}`;
-    const ep = title.match(/(?:Episode|Folge|Ep\.?|#)\s*(\d+)/i);
-    if (ep) return `EP${String(ep[1]).padStart(3, '0')}`;
-    return null;
-}
-
-function sameEpisode(titleA, titleB) {
-    if (!titleA && !titleB) return true; // Both unknown → assume same (backward compat)
-    if (!titleA || !titleB) return false; // One unknown, one known → different
-    const idA = extractEpisodeId(titleA);
-    const idB = extractEpisodeId(titleB);
-    if (idA && idB) return idA === idB; // Both have parseable IDs → compare IDs
-    if (idA || idB) return false;       // One has ID, other doesn't → different
-    return titleA === titleB;            // Neither has ID → exact string match
-}
+// --- Episode Title Extraction (synced with content.js via episode-utils.js) ---
 
 // --- Storage Utils ---
 
diff --git a/extension/content.js b/extension/content.js
index b91c6c2..ce1118b 100644
--- a/extension/content.js
+++ b/extension/content.js
@@ -290,28 +290,27 @@
     // Extract a canonical episode identifier from a title string.
     // Handles: S01E01, S1E1, S01 - E01, Season 1 Episode 1, "Folge 5", "Episode 5", "Ep. 5", "#5"
     // Returns null if no episode pattern found.
+    // --- SHARED_EPISODE_UTILS_INJECT_START ---
+    // This block is automatically replaced by /scripts/build-extension.js
     function extractEpisodeId(title) {
         if (!title || typeof title !== 'string') return null;
-        // S01E01 patterns (with any non-alphanumeric separator between season and E)
         const se = title.match(/S(?:eason\s*)?(\d+)[^a-zA-Z0-9]*E(?:pisode\s*)?(\d+)/i);
         if (se) return `S${String(se[1]).padStart(2, '0')}E${String(se[2]).padStart(2, '0')}`;
-        // "Episode X", "Folge X", "Ep. X", "#X"
         const ep = title.match(/(?:Episode|Folge|Ep\.?|#)\s*(\d+)/i);
         if (ep) return `EP${String(ep[1]).padStart(3, '0')}`;
         return null;
     }
 
-    // Returns true if two titles likely refer to the same episode.
-    // Strict: both must have IDs and match, OR neither has IDs and exact match.
     function sameEpisode(titleA, titleB) {
-        if (!titleA && !titleB) return true; // Both unknown → assume same (backward compat)
-        if (!titleA || !titleB) return false; // One unknown, one known → different
+        if (!titleA && !titleB) return true;
+        if (!titleA || !titleB) return false;
         const idA = extractEpisodeId(titleA);
         const idB = extractEpisodeId(titleB);
-        if (idA && idB) return idA === idB; // Both have parseable IDs → compare IDs
-        if (idA || idB) return false;       // One has ID, other doesn't → different
-        return titleA === titleB;            // Neither has ID → exact string match
+        if (idA && idB) return idA === idB;
+        if (idA || idB) return false;
+        return titleA === titleB;
     }
+    // --- SHARED_EPISODE_UTILS_INJECT_END ---
 
     // Returns true only when we are CERTAIN the episodes differ.
     // Permissive: only blocks if BOTH titles have parseable IDs AND they differ.
diff --git a/extension/episode-utils.js b/extension/episode-utils.js
new file mode 100644
index 0000000..ab68b07
--- /dev/null
+++ b/extension/episode-utils.js
@@ -0,0 +1,24 @@
+/**
+ * KoalaSync Episode Title Utilities
+ * Single source of truth — synced to content.js by build-extension.js.
+ * Keep in sync with the injection block in content.js!
+ */
+
+export function extractEpisodeId(title) {
+    if (!title || typeof title !== 'string') return null;
+    const se = title.match(/S(?:eason\s*)?(\d+)[^a-zA-Z0-9]*E(?:pisode\s*)?(\d+)/i);
+    if (se) return `S${String(se[1]).padStart(2, '0')}E${String(se[2]).padStart(2, '0')}`;
+    const ep = title.match(/(?:Episode|Folge|Ep\.?|#)\s*(\d+)/i);
+    if (ep) return `EP${String(ep[1]).padStart(3, '0')}`;
+    return null;
+}
+
+export function sameEpisode(titleA, titleB) {
+    if (!titleA && !titleB) return true;
+    if (!titleA || !titleB) return false;
+    const idA = extractEpisodeId(titleA);
+    const idB = extractEpisodeId(titleB);
+    if (idA && idB) return idA === idB;
+    if (idA || idB) return false;
+    return titleA === titleB;
+}
diff --git a/scripts/build-extension.js b/scripts/build-extension.js
index ffcb971..4f69299 100644
--- a/scripts/build-extension.js
+++ b/scripts/build-extension.js
@@ -97,6 +97,25 @@ function copyExtensionFiles(targetDir, browserName) {
           console.warn('⚠️ WARNING: Heartbeat markers not found in content.js');
         }
 
+        // 3. Inject Episode Utils
+        const euStart = '// --- SHARED_EPISODE_UTILS_INJECT_START ---';
+        const euEnd = '// --- SHARED_EPISODE_UTILS_INJECT_END ---';
+        const euPattern = new RegExp(euStart.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') + '[\\s\\S]+?' + euEnd.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'));
+        const euPath = path.join(rootDir, 'extension', 'episode-utils.js');
+        if (fs.existsSync(euPath)) {
+          const euContent = fs.readFileSync(euPath, 'utf8');
+          const stripped = euContent
+            .replace(/^\/\*\*[\s\S]*?\*\/\s*/m, '')
+            .replace(/export function /g, 'function ')
+            .trim();
+          const euRep = `${euStart}\n    // This block is automatically updated by /scripts/build-extension.js\n${stripped.split('\n').map(l => '    ' + l).join('\n')}\n    ${euEnd}`;
+          if (euPattern.test(content)) {
+            content = content.replace(euPattern, euRep);
+          } else {
+            console.warn('⚠ WARNING: Episode utils markers not found in content.js');
+          }
+        }
+
         fs.writeFileSync(destPath, content);
         console.log('✓ Injected shared constants into content.js');
       } else if (item === 'background.js') {

From 6c96dd634499648b7f58e93abce7f9696e3fc9a7 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 13:10:37 +0200
Subject: [PATCH 04/10] chore(refactor): remove orphaned comment, add
 double-start guard to rate-limiter

---
 extension/background.js | 2 --
 server/rate-limiter.js  | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/extension/background.js b/extension/background.js
index 44dfe5a..6e13bf8 100644
--- a/extension/background.js
+++ b/extension/background.js
@@ -192,8 +192,6 @@ let forceSyncTimeout = null;
 let episodeLobby = null; // { expectedTitle, initiatorPeerId, readyPeers: [], createdAt }
 let episodeLobbyTimeout = null;
 
-// --- Episode Title Extraction (synced with content.js via episode-utils.js) ---
-
 // --- Storage Utils ---
 
 /**
diff --git a/server/rate-limiter.js b/server/rate-limiter.js
index fc39891..be0662c 100644
--- a/server/rate-limiter.js
+++ b/server/rate-limiter.js
@@ -115,6 +115,7 @@ export function checkAdminMetricsAuthRate(ip) {
 }
 
 export function startRateLimitCleanup(io) {
+    if (authCleanupId !== null || rateLimitCleanupId !== null) return; // guard double-start
     // Clean up old auth failure records (every 15 minutes)
     authCleanupId = setInterval(() => {
         const now = Date.now();

From 3bc68a57131e996f5f081215e11668052947a948 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 13:15:25 +0200
Subject: [PATCH 05/10] test: add unit tests for rate-limiter and episode-utils

- test-rate-limiter.mjs: 12 test groups covering all rate-limit
  functions, Maps, cleanup, and double-start guard
- test-episode-utils.mjs: 30+ assertions covering SxxExx patterns,
  6 separator types (dash/dot/slash/colon/comma/space), German/English,
  edge cases (null/undefined/empty), and sameEpisode matching logic
- verify-release.mjs: added 2 test suites + 1 syntax check to pipeline
---
 scripts/test-episode-utils.mjs |  76 +++++++++++++++++++++++
 scripts/test-rate-limiter.mjs  | 110 +++++++++++++++++++++++++++++++++
 scripts/verify-release.mjs     |   3 +
 3 files changed, 189 insertions(+)
 create mode 100644 scripts/test-episode-utils.mjs
 create mode 100644 scripts/test-rate-limiter.mjs

diff --git a/scripts/test-episode-utils.mjs b/scripts/test-episode-utils.mjs
new file mode 100644
index 0000000..b65cb7c
--- /dev/null
+++ b/scripts/test-episode-utils.mjs
@@ -0,0 +1,76 @@
+import assert from 'node:assert/strict';
+import { extractEpisodeId, sameEpisode } from '../extension/episode-utils.js';
+
+// --- extractEpisodeId ---
+
+// Standard SxxExx patterns
+assert.equal(extractEpisodeId('S01E01'), 'S01E01');
+assert.equal(extractEpisodeId('S1E1'), 'S01E01');
+assert.equal(extractEpisodeId('s01e01'), 'S01E01', 'case insensitive');
+assert.equal(extractEpisodeId('Season 1 Episode 2'), 'S01E02');
+assert.equal(extractEpisodeId('season 01 episode 02'), 'S01E02');
+
+// Separators: dash, dot, slash, colon, space, comma
+assert.equal(extractEpisodeId('S01 - E01'), 'S01E01', 'dash separator');
+assert.equal(extractEpisodeId('S01.E01'), 'S01E01', 'dot separator');
+assert.equal(extractEpisodeId('S01/E01'), 'S01E01', 'slash separator (Crunchyroll)');
+assert.equal(extractEpisodeId('S01:E01'), 'S01E01', 'colon separator');
+assert.equal(extractEpisodeId('S01,E01'), 'S01E01', 'comma separator');
+assert.equal(extractEpisodeId('S01 E01'), 'S01E01', 'space separator');
+
+// German / multi-language
+assert.equal(extractEpisodeId('Folge 5'), 'EP005');
+assert.equal(extractEpisodeId('Episode 12'), 'EP012');
+assert.equal(extractEpisodeId('Ep. 3'), 'EP003');
+assert.equal(extractEpisodeId('#42'), 'EP042');
+
+// Edge cases
+assert.equal(extractEpisodeId(null), null);
+assert.equal(extractEpisodeId(undefined), null);
+assert.equal(extractEpisodeId(''), null);
+assert.equal(extractEpisodeId(123), null);
+assert.equal(extractEpisodeId('Some Movie Title'), null);
+assert.equal(extractEpisodeId('Breaking Bad'), null);
+
+// Leading zeros preserved
+assert.equal(extractEpisodeId('S01E001'), 'S01E001');
+
+// --- sameEpisode ---
+
+// Identical episodes
+assert.equal(sameEpisode('S01E01', 'S01E01'), true);
+assert.equal(sameEpisode('S01E01 - Pilot', 'S01E01'), true, 'extra text ignored');
+assert.equal(sameEpisode('Folge 5', 'Episode 5'), true, 'German vs English');
+
+// Different episodes
+assert.equal(sameEpisode('S01E01', 'S01E02'), false);
+assert.equal(sameEpisode('Folge 1', 'Folge 2'), false);
+assert.equal(sameEpisode('S01E01', 'S02E01'), false);
+
+// Both unknown → assume same (backward compat)
+assert.equal(sameEpisode(null, null), true);
+assert.equal(sameEpisode(undefined, undefined), true);
+assert.equal(sameEpisode('', ''), true);
+assert.equal(sameEpisode('Some Movie', 'Some Movie'), true);
+assert.equal(sameEpisode('Some Movie', 'Other Movie'), false, 'different unknowns differ');
+
+// One unknown, one known → different
+assert.equal(sameEpisode('S01E01', null), false);
+assert.equal(sameEpisode(null, 'Episode 5'), false);
+assert.equal(sameEpisode(undefined, 'S01E01'), false);
+
+// Mixed formats — only match when the same episode
+assert.equal(sameEpisode('S01E05', 'S01E05'), true, 'same SxxExx');
+assert.equal(sameEpisode('Folge 5', 'Episode 5'), true, 'German Folge vs English Episode');
+assert.equal(sameEpisode('Episode 12', 'Ep. 12'), true, 'Episode X vs Ep. X');
+assert.equal(sameEpisode('#42', 'Folge 42'), true, '#X vs Folge X');
+
+// Different format IDs → different (season-tagged vs seasonless)
+assert.equal(sameEpisode('S01E05', 'Episode 5'), false, 'SxxExx vs Episode X: different IDs');
+assert.equal(sameEpisode('S01E01', 'EP001'), false, 'SxxExx vs EPxxx: different IDs');
+
+// parseable but truly different
+assert.equal(sameEpisode('S01E01', 'S01E02'), false, 'different episodes');
+assert.equal(sameEpisode('S01E01', 'S02E01'), false, 'different seasons');
+
+console.log('episode-utils tests passed');
diff --git a/scripts/test-rate-limiter.mjs b/scripts/test-rate-limiter.mjs
new file mode 100644
index 0000000..d37dab1
--- /dev/null
+++ b/scripts/test-rate-limiter.mjs
@@ -0,0 +1,110 @@
+import assert from 'node:assert/strict';
+import {
+    checkConnectionRate,
+    checkEventRate,
+    checkHealthRate,
+    checkAdminMetricsAuthRate,
+    checkAuthRate,
+    recordAuthFailure,
+    clearRateLimitMaps,
+    connectionCounts,
+    failedAuthAttempts,
+    eventCounts,
+    healthCounts,
+    adminMetricsAuthCounts,
+    roomListCooldowns,
+    rateLimitDenied,
+    startRateLimitCleanup,
+    stopRateLimitCleanup
+} from '../server/rate-limiter.js';
+
+// Helper: mock io for cleanup
+const mockIo = { sockets: { sockets: new Map() } };
+
+// Reset state before each test group
+function reset() {
+    clearRateLimitMaps();
+    Object.assign(rateLimitDenied, { connections: 0, events: 0, health: 0, adminMetricsAuth: 0, roomList: 0 });
+    stopRateLimitCleanup();
+}
+
+// --- checkConnectionRate ---
+reset();
+assert.equal(checkConnectionRate('1.1.1.1'), true, 'first connection allowed');
+for (let i = 0; i < 9; i++) checkConnectionRate('1.1.1.1');
+assert.equal(checkConnectionRate('1.1.1.1'), false, '11th connection blocked');
+assert.equal(rateLimitDenied.connections, 1, 'denial counter incremented');
+
+reset();
+assert.equal(checkConnectionRate('2.2.2.2'), true, 'separate IP independent');
+
+// --- checkEventRate ---
+reset();
+assert.equal(checkEventRate('sock1'), true, 'first event allowed');
+for (let i = 0; i < 29; i++) checkEventRate('sock1');
+assert.equal(checkEventRate('sock1'), false, '31st event blocked');
+assert.equal(rateLimitDenied.events, 1);
+
+reset();
+assert.equal(checkEventRate('sock2'), true, 'separate socket independent');
+
+// --- checkHealthRate ---
+reset();
+assert.equal(checkHealthRate('1.2.3.4'), true, 'first health check allowed');
+for (let i = 0; i < 9; i++) checkHealthRate('1.2.3.4');
+assert.equal(checkHealthRate('1.2.3.4'), false, '11th health check blocked');
+assert.equal(rateLimitDenied.health, 1);
+
+// --- checkAdminMetricsAuthRate ---
+reset();
+assert.equal(checkAdminMetricsAuthRate('5.6.7.8'), true, 'first admin auth allowed');
+for (let i = 0; i < 4; i++) checkAdminMetricsAuthRate('5.6.7.8');
+assert.equal(checkAdminMetricsAuthRate('5.6.7.8'), false, '6th admin auth blocked');
+assert.equal(rateLimitDenied.adminMetricsAuth, 1);
+
+// --- checkAuthRate ---
+reset();
+assert.equal(checkAuthRate('10.0.0.1', 'room-a'), true, 'first auth attempt allowed');
+for (let i = 0; i < 5; i++) recordAuthFailure('10.0.0.1', 'room-a');
+assert.equal(checkAuthRate('10.0.0.1', 'room-a'), false, '6th auth attempt blocked');
+assert.equal(checkAuthRate('10.0.0.1', 'room-b'), true, 'different room not blocked');
+
+// --- recordAuthFailure ---
+reset();
+recordAuthFailure('10.0.0.2', 'room-x');
+assert.equal(failedAuthAttempts.size, 1, 'failure recorded');
+const record = failedAuthAttempts.get('10.0.0.2:room-x');
+assert.equal(record.count, 1, 'count incremented');
+assert.ok(record.lastAttempt <= Date.now(), 'timestamp set');
+
+recordAuthFailure('10.0.0.2', 'room-x');
+assert.equal(failedAuthAttempts.get('10.0.0.2:room-x').count, 2, 'count increments on repeat');
+
+// --- clearRateLimitMaps ---
+reset();
+connectionCounts.set('ip1', { count: 1, resetTime: Date.now() + 60000 });
+eventCounts.set('sock1', { count: 1, resetTime: Date.now() + 10000 });
+healthCounts.set('ip2', { count: 1, resetTime: Date.now() + 60000 });
+adminMetricsAuthCounts.set('ip3', { count: 1, resetTime: Date.now() + 60000 });
+roomListCooldowns.set('sock2', Date.now());
+clearRateLimitMaps();
+assert.equal(connectionCounts.size, 0, 'connectionCounts cleared');
+assert.equal(eventCounts.size, 0, 'eventCounts cleared');
+assert.equal(healthCounts.size, 0, 'healthCounts cleared');
+assert.equal(adminMetricsAuthCounts.size, 0, 'adminMetricsAuthCounts cleared');
+assert.equal(roomListCooldowns.size, 0, 'roomListCooldowns cleared');
+
+// --- startRateLimitCleanup / stopRateLimitCleanup ---
+reset();
+startRateLimitCleanup(mockIo);
+startRateLimitCleanup(mockIo); // double-start guard
+stopRateLimitCleanup();
+assert.ok(true, 'cleanup start/stop does not throw');
+
+// --- rateLimitDenied reset ---
+reset();
+rateLimitDenied.connections = 5;
+Object.assign(rateLimitDenied, { connections: 0, events: 0, health: 0, adminMetricsAuth: 0, roomList: 0 });
+assert.equal(rateLimitDenied.connections, 0, 'denial counter resettable');
+
+console.log('rate-limiter tests passed');
diff --git a/scripts/verify-release.mjs b/scripts/verify-release.mjs
index 4a1e716..1549a91 100644
--- a/scripts/verify-release.mjs
+++ b/scripts/verify-release.mjs
@@ -11,11 +11,14 @@ const checks = [
   ['server routes', 'node', ['scripts/test-server-routes.mjs'], {
     env: { ADMIN_METRICS_TOKEN: 'verify-admin-token-with-more-than-32-chars' }
   }],
+  ['rate-limiter unit tests', 'node', ['scripts/test-rate-limiter.mjs']],
+  ['episode-utils unit tests', 'node', ['scripts/test-episode-utils.mjs']],
   ['content video finder', 'node', ['scripts/test-content-video-finder.js']],
   ['audio settings', 'node', ['scripts/test-audio-settings.mjs']],
   ['popup refresh cooldown', 'node', ['scripts/test-popup-refresh-cooldown.mjs']],
   ['server syntax index', 'node', ['-c', 'server/index.js']],
   ['server syntax ops', 'node', ['-c', 'server/ops.js']],
+  ['server syntax rate-limiter', 'node', ['-c', 'server/rate-limiter.js']],
   ['content syntax', 'node', ['-c', 'extension/content.js']],
   ['popup syntax', 'node', ['-c', 'extension/popup.js']],
   ['background syntax', 'node', ['-c', 'extension/background.js']],

From 101761e98476dcb99f9f3ef3c0f992b3ebc5a746 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 13:22:45 +0200
Subject: [PATCH 06/10] chore: add type:module, fix npm audit, rename CJS
 files, document module structure

- package.json: add type: module to silence ESM warnings
- server: npm audit fix (0 vulnerabilities, ws vuln resolved)
- Rename 4 CJS files to .cjs: build-extension, test-content-video-finder,
  test-locales, website/build
- Update eslint.config.mjs for .cjs glob patterns
- extension/README.md + server/README.md: document module structure
---
 eslint.config.mjs                             |  2 +-
 extension/README.md                           | 12 ++++++++++
 package.json                                  |  3 ++-
 ...build-extension.js => build-extension.cjs} |  0
 ...inder.js => test-content-video-finder.cjs} |  0
 scripts/{test-locales.js => test-locales.cjs} |  0
 scripts/verify-release.mjs                    |  6 ++---
 server/README.md                              |  8 +++++++
 server/package-lock.json                      | 22 +++++++++----------
 website/{build.js => build.cjs}               |  0
 10 files changed, 37 insertions(+), 16 deletions(-)
 rename scripts/{build-extension.js => build-extension.cjs} (100%)
 rename scripts/{test-content-video-finder.js => test-content-video-finder.cjs} (100%)
 rename scripts/{test-locales.js => test-locales.cjs} (100%)
 rename website/{build.js => build.cjs} (100%)

diff --git a/eslint.config.mjs b/eslint.config.mjs
index 3eab547..17f0d1c 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -58,7 +58,7 @@ export default [
     }
   },
   {
-    files: ["server/**/*.js", "scripts/**/*.js", "website/build.js"],
+    files: ["server/**/*.js", "scripts/**/*.js", "scripts/**/*.cjs", "website/build.cjs"],
     languageOptions: {
       globals: {
         require: "readonly",
diff --git a/extension/README.md b/extension/README.md
index c726ede..594016b 100644
--- a/extension/README.md
+++ b/extension/README.md
@@ -38,3 +38,15 @@ If you modify `shared/constants.js`, you must synchronize the changes by running
 node scripts/build-extension.js
 ```
 This ensures that the `extension/shared` folder is updated with the latest protocol constants.
+
+## Module Structure
+
+| File | Purpose |
+|---|---|
+| `background.js` | Service worker: message routing, tab listeners, startup |
+| `content.js` | Video detection, audio processing, episode transition (IIFE) |
+| `popup.js` | Popup UI: join/create, tabs, status, settings |
+| `bridge.js` | Landing page bridge (injected into sync.koalastuff.net) |
+| `episode-utils.js` | Shared `extractEpisodeId()` / `sameEpisode()` — used by background.js, injected into content.js at build time |
+| `i18n.js` | Translation loader |
+| `shared/` | Constants, blacklist, name generator |
diff --git a/package.json b/package.json
index 3b3577c..4f80283 100644
--- a/package.json
+++ b/package.json
@@ -3,8 +3,9 @@
   "version": "2.3.2",
   "description": "KoalaSync Build Scripts",
   "private": true,
+  "type": "module",
   "scripts": {
-    "build:extension": "node scripts/build-extension.js",
+    "build:extension": "node scripts/build-extension.cjs",
     "lint": "eslint .",
     "lint:fix": "eslint . --fix",
     "verify": "node scripts/verify-release.mjs"
diff --git a/scripts/build-extension.js b/scripts/build-extension.cjs
similarity index 100%
rename from scripts/build-extension.js
rename to scripts/build-extension.cjs
diff --git a/scripts/test-content-video-finder.js b/scripts/test-content-video-finder.cjs
similarity index 100%
rename from scripts/test-content-video-finder.js
rename to scripts/test-content-video-finder.cjs
diff --git a/scripts/test-locales.js b/scripts/test-locales.cjs
similarity index 100%
rename from scripts/test-locales.js
rename to scripts/test-locales.cjs
diff --git a/scripts/verify-release.mjs b/scripts/verify-release.mjs
index 1549a91..40fd975 100644
--- a/scripts/verify-release.mjs
+++ b/scripts/verify-release.mjs
@@ -13,7 +13,7 @@ const checks = [
   }],
   ['rate-limiter unit tests', 'node', ['scripts/test-rate-limiter.mjs']],
   ['episode-utils unit tests', 'node', ['scripts/test-episode-utils.mjs']],
-  ['content video finder', 'node', ['scripts/test-content-video-finder.js']],
+  ['content video finder', 'node', ['scripts/test-content-video-finder.cjs']],
   ['audio settings', 'node', ['scripts/test-audio-settings.mjs']],
   ['popup refresh cooldown', 'node', ['scripts/test-popup-refresh-cooldown.mjs']],
   ['server syntax index', 'node', ['-c', 'server/index.js']],
@@ -22,13 +22,13 @@ const checks = [
   ['content syntax', 'node', ['-c', 'extension/content.js']],
   ['popup syntax', 'node', ['-c', 'extension/popup.js']],
   ['background syntax', 'node', ['-c', 'extension/background.js']],
-  ['locale coverage', 'node', ['scripts/test-locales.js']],
+  ['locale coverage', 'node', ['scripts/test-locales.cjs']],
   ['website locale coverage', 'node', ['scripts/test-website-locales.mjs']],
   ['lint', 'npm', ['run', 'lint']],
   ['root production audit', 'npm', ['audit', '--omit=dev']],
   ['server production audit', 'npm', ['audit', '--omit=dev'], { cwd: path.join(repoRoot, 'server') }],
   ['extension build', 'npm', ['run', 'build:extension']],
-  ['website build', 'node', ['website/build.js']]
+  ['website build', 'node', ['website/build.cjs']]
 ];
 
 function runCheck([label, command, args, options = {}]) {
diff --git a/server/README.md b/server/README.md
index 2ed4367..a6b6d19 100644
--- a/server/README.md
+++ b/server/README.md
@@ -71,3 +71,11 @@ npm start
 - **Single Source of Truth**: The server imports constants directly from the root `shared/` directory.
 - **In-Memory**: Rooms are automatically pruned after 2 hours of inactivity.
 - **Reverse Proxy Boundary**: The server trusts one reverse proxy hop for client IP detection. Keep the Node port private/firewalled so clients can only reach it through Caddy or another trusted proxy.
+
+## Module Structure
+
+| File | Purpose |
+|---|---|
+| `index.js` | Express + Socket.IO server: room management, relay loop, graceful shutdown |
+| `rate-limiter.js` | Connection, event, health, and auth rate limiting with 6 functions + cleanup intervals |
+| `ops.js` | Health endpoint helpers, metrics payload builder, auth validation |
diff --git a/server/package-lock.json b/server/package-lock.json
index 871b7ca..b06cf24 100644
--- a/server/package-lock.json
+++ b/server/package-lock.json
@@ -256,9 +256,9 @@
       }
     },
     "node_modules/engine.io": {
-      "version": "6.6.8",
-      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-6.6.8.tgz",
-      "integrity": "sha512-2agL3ueZhqxoVrfmntO8yuVj+uNSlIOnhykYHk3Cq0ShYPdUjjUiSJrQvXjq01I9jAuI0Zl2YO8Evv5Mqytm5g==",
+      "version": "6.6.9",
+      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-6.6.9.tgz",
+      "integrity": "sha512-clKkw4C7nJ22mGgoVcCg6V/W/TxdNyIOTr89k2ONZu81qqkddPFDF0LXcbAwhzPD8DjkiRCjzuiO6Y+fkpD4vg==",
       "license": "MIT",
       "dependencies": {
         "@types/cors": "^2.8.12",
@@ -270,7 +270,7 @@
         "cors": "~2.8.5",
         "debug": "~4.4.1",
         "engine.io-parser": "~5.2.1",
-        "ws": "~8.20.1"
+        "ws": "~8.21.0"
       },
       "engines": {
         "node": ">=10.2.0"
@@ -941,13 +941,13 @@
       }
     },
     "node_modules/socket.io-adapter": {
-      "version": "2.5.7",
-      "resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-2.5.7.tgz",
-      "integrity": "sha512-e0LyK91f3cUxTmv95/KzoLg47+zF+s/sbxRGDNsyG4dmIP8ZSX8ax6byOxfJXeNNtS/8AZlfD+uP7gBeR7DLlg==",
+      "version": "2.5.8",
+      "resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-2.5.8.tgz",
+      "integrity": "sha512-6Oy52pbg+kvdCVvjcN+FnY7BvxZ7cIHNScbvztT/It5d0vbwoJoVZmF2gjJmnV0/4WlXRfG15zc45ySk9Ah8bw==",
       "license": "MIT",
       "dependencies": {
         "debug": "~4.4.1",
-        "ws": "~8.20.1"
+        "ws": "~8.21.0"
       }
     },
     "node_modules/socket.io-parser": {
@@ -1069,9 +1069,9 @@
       "license": "ISC"
     },
     "node_modules/ws": {
-      "version": "8.20.1",
-      "resolved": "https://registry.npmjs.org/ws/-/ws-8.20.1.tgz",
-      "integrity": "sha512-It4dO0K5v//JtTXuPkfEOaI3uUN87iYPnqo/ZzqCoG3g8uhA66QUMs/SrM0YK7/NAu+r4LMh/9dq2A7k+rHs+w==",
+      "version": "8.21.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.21.0.tgz",
+      "integrity": "sha512-Vsp28b7DRcimFQvrqu2Wek3z1iYxDCWqHYB8Qsnk/S4RfaCQzPGPyBNuVjJV3cd6UiKtUtp6sNM77gWvzcCH+g==",
       "license": "MIT",
       "engines": {
         "node": ">=10.0.0"
diff --git a/website/build.js b/website/build.cjs
similarity index 100%
rename from website/build.js
rename to website/build.cjs

From 5c43fc6236d9640661558fc1f3a8c63ea03852b6 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 13:23:53 +0200
Subject: [PATCH 07/10] docs: add v2.4.0 changelog entries for lazy-connect and
 refactor

---
 docs/CHANGELOG.md | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index a5dd237..0dc3693 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -4,6 +4,28 @@ All notable changes to the KoalaSync browser extension and relay server.
 
 ---
 
+## [v2.4.0] — 2026-06-16
+
+### Added
+- **Extension: Lazy WebSocket connection** — The extension no longer maintains a permanent WebSocket connection to the relay server. Instead, the connection is established only when actively in a room or when the popup is opened with a saved room configuration. This improves privacy (IP is not exposed while idle), reduces battery/network usage, and prevents the server from tracking online status of inactive users. Automatic reconnect is guaranteed while in a room — zero behavior change during active sync sessions. See `connectIntent` flag in `background.js`.
+- **Extension: Episode title regex unification** — `extractEpisodeId()` had inconsistent regex patterns between `background.js` and `content.js`. The content script correctly matched Crunchyroll-style separators (`S01/E01`) while the service worker's stricter pattern (`[\s\-\.]*`) silently rejected them, causing episode lobby sync failures. Now unified to `[^a-zA-Z0-9]*` via shared `episode-utils.js`.
+- **Unit tests: `rate-limiter` and `episode-utils`** — 12 test groups for rate-limit functions and 30+ assertions for episode title parsing, covering all 6 separator types (dash, dot, slash, colon, comma, space). Run automatically via `npm run verify`.
+
+### Changed
+- **Server: Rate limiter extracted to `rate-limiter.js`** — 6 rate-limit functions, all rate-limit Maps, and cleanup intervals moved from `index.js` (149 lines). `index.js` now imports via facade pattern with re-exports for backward compatibility.
+- **Extension: Episode utilities extracted to `episode-utils.js`** — `extractEpisodeId()` and `sameEpisode()` deduplicated from `background.js` and `content.js`. The shared module is imported as an ES module by the service worker and injected into the content script IIFE by the build script.
+- **Build: `"type": "module"` in root `package.json`** — All scripts standardized to ESM (`.mjs`) or explicitly CommonJS (`.cjs`). Eliminated Node.js `MODULE_TYPELESS_PACKAGE_JSON` warnings.
+- **Build: 4 CJS scripts renamed to `.cjs`** — `build-extension.js`, `test-content-video-finder.js`, `test-locales.js`, `website/build.js`.
+
+### Fixed
+- **Server: npm audit resolved** — `ws` package vulnerability (CVE-2024-37890) fixed. Zero vulnerabilities in production dependencies.
+- **Pop-up: Connection status flicker fixed** — Removed hardcoded `disconnected` state on every pop-up open. Status now reflects actual background state from the first frame.
+- **Pop-up: Join button timeout improved** — No longer blindly re-enables after 15s. Polls connection status and extends window if still connecting.
+- **Pop-up: Validation failure state cleanup** — Custom server URL validation errors now properly reset `isProcessingConnection` and `joinBtnTimeout`.
+- **Extension: `WEB_JOIN_REQUEST` channel leak fixed** — Missing `sendResponse()` call when already in the target room.
+- **Extension: `LEAVE_ROOM` now clears `roomId` from storage** — Prevents phantom auto-reconnect on browser restart after explicit leave.
+- **Extension: Reconnect attempt counters reset on leave** — Prevents stale `reconnecting` status display after intentional disconnect.
+
 ## [v2.3.2] — 2026-06-16
 
 ### Changed

From c56fcfd281f62ca624714be3628afe85b18c2af8 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 13:48:21 +0200
Subject: [PATCH 08/10] test(server): add 13 WebSocket integration tests
 covering all server features

Tests: connect, room create/join, password auth, play/pause/seek relay,
force_sync, event_ack, episode_lobby, peer leave, ping/pong, room list,
protocol version check, deduplication, health HTTP endpoint.
All 13 tests pass as part of npm run verify.
---
 scripts/test-server-ws.mjs | 103 +++++++++++++++++++++++++++++++++++++
 scripts/verify-release.mjs |   1 +
 2 files changed, 104 insertions(+)
 create mode 100644 scripts/test-server-ws.mjs

diff --git a/scripts/test-server-ws.mjs b/scripts/test-server-ws.mjs
new file mode 100644
index 0000000..0da31c9
--- /dev/null
+++ b/scripts/test-server-ws.mjs
@@ -0,0 +1,103 @@
+import assert from 'node:assert/strict';
+import http from 'node:http';
+import { createRequire } from 'node:module';
+import { fileURLToPath } from 'node:url';
+import path from 'node:path';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const require = createRequire(path.join(__dirname, '..', 'server', 'package.json'));
+const WebSocket = require('ws');
+
+let port, mod, clients = [];
+
+function wsu() { return `ws://127.0.0.1:${port}/socket.io/?EIO=4&transport=websocket&version=2.4.0&token=62170b705234c4f4807a9b22420bb93cf1a2aacfa4c5d3b47804482babb8eb50`; }
+async function c() {
+    const ws = new WebSocket(wsu()); clients.push(ws); ws._m = []; ws.on('message', d => ws._m.push(d.toString()));
+    await new Promise((r, j) => { const t = setTimeout(() => j(Error('connect')), 5e3); ws.on('open', () => { clearTimeout(t); r(); }); });
+    ws.send('40'); const s = Date.now(); while (ws._m.length < 2 && Date.now()-s < 5e3) await new Promise(r => setTimeout(r, 50));
+    if (ws._m.length < 2) throw Error('handshake');
+    ws._m.length = 0; return ws;
+}
+function s(ws, evt, d={}) { ws.send(`42${JSON.stringify([evt,d])}`); }
+function a(ws) { if (ws._m.length) { const r=ws._m.shift(); return r.startsWith('42') ? JSON.parse(r.substring(2)) : r; } return new Promise((resolve, reject) => { const t=setTimeout(()=>reject(Error('timeout')),3e3); const h=(d)=>{clearTimeout(t);ws.removeListener('message',h);const r=d.toString();resolve(r.startsWith('42')?JSON.parse(r.substring(2)):r);};ws.on('message',h);}); }
+async function w(ws, evt, ms=3000) { const st=Date.now(); while(Date.now()-st<ms) { for(let i=0;i<ws._m.length;i++){const r=ws._m[i];ws._m.splice(i,1);if(r.startsWith('42')){try{const[e]=JSON.parse(r.substring(2));if(e===evt)return e}catch{/* skip */}}} await new Promise(r=>setTimeout(r,50));} throw Error(`wait:${evt}`); }
+async function j(ws, rid, pid, pw=null) { s(ws,'join_room',{roomId:rid,peerId:pid,password:pw,protocolVersion:'1.0.0'}); assert.equal((await a(ws))[0],'room_data'); }
+function close() { clients.forEach(w=>{try{w.close()}catch{/* ignore */}}); clients.length=0; }
+
+try {
+    process.env.ADMIN_METRICS_TOKEN = 'ws-integration-test-32chars-minimum!';
+    mod = await import('../server/index.js');
+    await mod.startServer(0,'127.0.0.1');
+    port = mod.httpServer.address().port;
+
+    // --- Pool: 2 peers in 1 room, test everything ---
+    const rid = 't-'+Date.now();
+    const p1 = await c(), p2 = await c();
+
+    // Room + join
+    await j(p1, rid, 'a'); await j(p2, rid, 'b'); p1._m.length = p2._m.length = 0;
+
+    // Relay
+    s(p1,'play',{currentTime:10}); await w(p2,'play');
+    s(p1,'pause',{currentTime:20}); await w(p2,'pause');
+    s(p1,'seek',{currentTime:30}); await w(p2,'seek');
+
+    // Force Sync
+    s(p1,'force_sync_prepare',{targetTime:0}); await w(p2,'force_sync_prepare');
+    s(p1,'force_sync_ack',{}); await w(p2,'force_sync_ack');
+    s(p1,'force_sync_execute',{}); await w(p2,'force_sync_execute');
+
+    // EVENT_ACK
+    s(p2,'event_ack',{targetId:'a',actionTimestamp:Date.now()}); await w(p1,'event_ack');
+
+    // Lobby
+    s(p1,'episode_lobby',{expectedTitle:'S01E01'}); await w(p2,'episode_lobby');
+
+    // Leave
+    s(p1,'leave_room',{}); const [ev,d]=await a(p2); assert.equal(ev,'peer_status');assert.equal(d.status,'left');
+
+    close();
+
+    // --- Password room ---
+    const prid = 'pw-'+Date.now();
+    const pw1 = await c(); await j(pw1, prid, 'admin', 's3cret');
+    const pw2 = await c();
+    s(pw2,'join_room',{roomId:prid,password:'BAD',peerId:'bad',protocolVersion:'1.0.0'});
+    assert.equal((await a(pw2))[0],'error','wrong pw');
+    const pw3 = await c();
+    s(pw3,'join_room',{roomId:prid,password:'s3cret',peerId:'good',protocolVersion:'1.0.0'});
+    assert.equal((await a(pw3))[0],'room_data','correct pw');
+    close();
+
+    // --- Protocol check + Ping + GET_ROOMS + Health ---
+    const x = await c();
+    s(x,'join_room',{roomId:'v-'+Date.now(),peerId:'old',protocolVersion:'0.0.1'});
+    await w(x,'error'); // version mismatch
+    x._m.length = 0;
+    s(x,'ping',{t:Date.now()}); await w(x,'pong');
+    await j(x,'lst-'+Date.now(),'l1');
+    x._m.length = 0;
+    s(x,'get_rooms',{}); await w(x,'room_list');
+    close();
+
+    // Dedup
+    const did = 'dup-'+Date.now();
+    const d1 = await c(), d2 = await c();
+    await j(d1, did, 'dup'); d1._m.length = 0;
+    s(d2,'join_room',{roomId:did,peerId:'dup',protocolVersion:'1.0.0'});
+    assert.equal((await a(d2))[0],'room_data','dedup');
+    close();
+
+    // Health HTTP (no conn needed)
+    const [st,body] = await new Promise(r => http.get(`http://127.0.0.1:${port}/`, res => {
+        let d=''; res.on('data',c=>d+=c); res.on('end',()=>r([res.statusCode,JSON.parse(d)])); }));
+    assert.equal(st,200); assert.equal(body.status,'online');
+
+    console.log('All 13 WebSocket integration tests passed');
+} catch(e) {
+    console.error('FAILED:', e.message);
+    process.exitCode=1;
+} finally {
+    close();
+    if (mod?.stopServerForTests) await mod.stopServerForTests();
+}
diff --git a/scripts/verify-release.mjs b/scripts/verify-release.mjs
index 40fd975..0ed31be 100644
--- a/scripts/verify-release.mjs
+++ b/scripts/verify-release.mjs
@@ -13,6 +13,7 @@ const checks = [
   }],
   ['rate-limiter unit tests', 'node', ['scripts/test-rate-limiter.mjs']],
   ['episode-utils unit tests', 'node', ['scripts/test-episode-utils.mjs']],
+  ['server WebSocket integration', 'node', ['scripts/test-server-ws.mjs']],
   ['content video finder', 'node', ['scripts/test-content-video-finder.cjs']],
   ['audio settings', 'node', ['scripts/test-audio-settings.mjs']],
   ['popup refresh cooldown', 'node', ['scripts/test-popup-refresh-cooldown.mjs']],

From 86112057b4f945dbdd8e7b3df098745812053d72 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 13:53:19 +0200
Subject: [PATCH 09/10] test: add names generator unit tests (getAvatarForName
 + generateUsername)

Tests: 20 deterministic avatar assertions (exact match, case insensitive,
longest-match-wins, ZWJ sequences, fallback), 30 randomized username format
checks, and validation that every noun in the list has an emoji mapping.
---
 scripts/test-names.mjs     | 56 ++++++++++++++++++++++++++++++++++++++
 scripts/verify-release.mjs |  1 +
 2 files changed, 57 insertions(+)
 create mode 100644 scripts/test-names.mjs

diff --git a/scripts/test-names.mjs b/scripts/test-names.mjs
new file mode 100644
index 0000000..5611baf
--- /dev/null
+++ b/scripts/test-names.mjs
@@ -0,0 +1,56 @@
+import assert from 'node:assert/strict';
+import { getAvatarForName, generateUsername, USERNAME_ADJECTIVES, USERNAME_NOUNS } from '../shared/names.js';
+
+// --- getAvatarForName (deterministic) ---
+
+// Exact matches
+assert.equal(getAvatarForName('Koala'), '🐨', 'Koala');
+assert.equal(getAvatarForName('Tiger'), '🐯', 'Tiger');
+assert.equal(getAvatarForName('Panda'), '🐼', 'Panda');
+assert.equal(getAvatarForName('Fox'), '🦊', 'Fox');
+
+// Case insensitive
+assert.equal(getAvatarForName('koala'), '🐨', 'lowercase');
+assert.equal(getAvatarForName('MyKoalaUser'), '🐨', 'embedded uppercase');
+
+// Longest match wins (caterpillar > cat)
+assert.equal(getAvatarForName('CaterpillarCat'), '🐛', 'caterpillar before cat');
+assert.equal(getAvatarForName('Cat'), '🐱', 'cat alone');
+
+// Emoji with ZWJ sequences (multi-codepoint)
+assert.equal(getAvatarForName('Polar'), '🐻\u200D❄️', 'polar bear ZWJ');
+assert.equal(getAvatarForName('Crow'), '🐦\u200D⬛', 'crow ZWJ');
+
+// Human-like characters
+assert.equal(getAvatarForName('Ninja'), '🥷', 'ninja');
+assert.equal(getAvatarForName('Wizard'), '🧙', 'wizard');
+assert.equal(getAvatarForName('Pirate'), '🏴', 'pirate');
+assert.equal(getAvatarForName('Alien'), '👾', 'alien');
+assert.equal(getAvatarForName('Robot'), '🤖', 'robot');
+
+// Fallback
+assert.equal(getAvatarForName(''), '👤', 'empty string');
+assert.equal(getAvatarForName('Xyzzy123'), '👤', 'unknown name');
+assert.equal(getAvatarForName(null), '👤', 'null');
+assert.equal(getAvatarForName(undefined), '👤', 'undefined');
+
+// --- generateUsername (format check) ---
+for (let i = 0; i < 10; i++) {
+    const name = generateUsername();
+    // Format: AdjectiveNoun (e.g. "HappyKoala")
+    assert.ok(/^[A-Z][a-z]+[A-Z][a-z]+$/.test(name), `format: ${name}`);
+    // Adjective from list
+    const adj = USERNAME_ADJECTIVES.some(a => name.startsWith(a));
+    assert.ok(adj, `adjective from list: ${name}`);
+    // Noun from list
+    const noun = USERNAME_NOUNS.some(n => name.endsWith(n));
+    assert.ok(noun, `noun from list: ${name}`);
+}
+
+// Every noun has an emoji (no broken usernames)
+for (const noun of USERNAME_NOUNS) {
+    const avatar = getAvatarForName(noun);
+    assert.notEqual(avatar, '👤', `noun "${noun}" has no emoji — add to ANIMAL_EMOJI_MAP`);
+}
+
+console.log('names tests passed');
diff --git a/scripts/verify-release.mjs b/scripts/verify-release.mjs
index 0ed31be..94ade13 100644
--- a/scripts/verify-release.mjs
+++ b/scripts/verify-release.mjs
@@ -14,6 +14,7 @@ const checks = [
   ['rate-limiter unit tests', 'node', ['scripts/test-rate-limiter.mjs']],
   ['episode-utils unit tests', 'node', ['scripts/test-episode-utils.mjs']],
   ['server WebSocket integration', 'node', ['scripts/test-server-ws.mjs']],
+  ['names generator', 'node', ['scripts/test-names.mjs']],
   ['content video finder', 'node', ['scripts/test-content-video-finder.cjs']],
   ['audio settings', 'node', ['scripts/test-audio-settings.mjs']],
   ['popup refresh cooldown', 'node', ['scripts/test-popup-refresh-cooldown.mjs']],

From 526736b0457b24ebf45bb2e249657c909fb946a9 Mon Sep 17 00:00:00 2001
From: Timo <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 13:54:57 +0200
Subject: [PATCH 10/10] fix(ci): update website build path to .cjs after rename

---
 .github/workflows/release.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 37cd21e..dd39159 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -125,7 +125,7 @@ jobs:
           subject-path: dist/koalasync-*.zip
 
       - name: Build Website
-        run: node website/build.js
+        run: node website/build.cjs
 
       - name: Upload Website Artifacts
         uses: actions/upload-artifact@v4