Add ESLint setup, fix 6 lint errors, update AI_INIT.md with lint checks

extension/background.js

@@ -7,7 +7,6 @@ const MAX_RECONNECT_DELAY = 30000;
 let isConnecting = false;
 let peerId = null; // initialized via getPeerId()
 let currentRoom = null;
-let lastPeersJson = null;
 let currentTabId = null;
 let currentTabTitle = null; // New: for Smart Matching
 let logs = [];
@@ -341,7 +340,7 @@ async function connect() {
                 try {
                     const payload = JSON.parse(msg.substring(2));
                     handleServerEvent(payload[0], payload[1]);
-                } catch (e) {
+                } catch (_e) {
                     addLog(`Failed to parse message: ${msg}`, 'error');
                 }
             }
@@ -894,7 +893,7 @@ async function routeToContent(action, payload) {
                 files: ['content.js']
             }).then(() => {
                 setTimeout(() => routeToContent(action, payload), 500);
-            }).catch(err => {
+            }).catch(_err => {
                 addLog(`Auto-reinject failed for tab ${tabId}`, 'warn');
             });
         } else {
@@ -941,7 +940,7 @@ function leaveOldRoomIfSwitching(newRoomId) {
         if (socket && socket.readyState === WebSocket.OPEN && isNamespaceJoined) {
             try {
                 socket.send(`42${JSON.stringify([EVENTS.LEAVE_ROOM, { peerId }])}`);
-            } catch (e) {
+            } catch (_e) {
                 addLog('Failed to send leave room packet during transition', 'error');
             }
         }
@@ -1356,7 +1355,7 @@ chrome.tabs.onRemoved.addListener((tabId) => {
 });
 
 // Re-inject on full page refresh
-chrome.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
+chrome.tabs.onUpdated.addListener((tabId, changeInfo, _tab) => {
     if (currentTabId && tabId === parseInt(currentTabId) && changeInfo.status === 'complete') {
         chrome.scripting.executeScript({
             target: { tabId },

extension/content.js

@@ -9,7 +9,7 @@
         if (window.koalaSyncInjected && chrome.runtime.id) {
             return;
         }
-    } catch (e) {
+    } catch (_e) {
         // Context invalidated, proceed with re-injection
     }
     window.koalaSyncInjected = true;
@@ -42,7 +42,7 @@
     // --- Episode Auto-Sync State ---
     let lastKnownMediaTitle = null;
     let episodeTransitionDebounce = null;
-    let pendingLobbyTitle = null; // Title we're waiting to match (from remote lobby)
+    let _pendingLobbyTitle = null; // Title we're waiting to match (from remote lobby)
     let lobbyPollTimer = null;
 
     function expectEvent(state) {
@@ -131,7 +131,7 @@
 
     function startLobbyPoll(expectedTitle) {
         stopLobbyPoll();
-        pendingLobbyTitle = expectedTitle;
+        _pendingLobbyTitle = expectedTitle;
 
         // NOTE: Do NOT pause here. Three callers reach this function:
         // 1. PAUSE_FOR_LOBBY (initiator): already paused by that handler before calling us.
@@ -151,7 +151,7 @@
 
 
     function stopLobbyPoll() {
-        pendingLobbyTitle = null;
+        _pendingLobbyTitle = null;
         if (lobbyPollTimer) {
             clearInterval(lobbyPollTimer);
             lobbyPollTimer = null;
@@ -223,7 +223,7 @@
                 expectEvent('seek');
                 video.currentTime = data.targetTime;
             }
-        } catch (e) {
+    } catch (e) {
             reportLog(`Media Action Error: ${e.message}`, 'error');
         }
     }

extension/popup.js

@@ -737,7 +737,7 @@ elements.joinBtn.addEventListener('click', async () => {
         try {
             const urlToCheck = serverUrl.includes('://') ? serverUrl : 'ws://' + serverUrl;
             new URL(urlToCheck);
-        } catch (e) {
+        } catch (_e) {
             showError('Invalid Server URL format.');
             elements.joinBtn.disabled = false;
             elements.joinBtn.textContent = 'Join Room';