release: v1.9.0 — command sequencing, episode-aware sync, echo suppression

- Add per-peer monotonically increasing seq numbers (localSeq + lastSeqBySender)
- Server relays seq for stale command detection (backward compatible)
- Replace expectedEvents (1500ms timeout) with _suppressTimers (per-type, 300ms)
- Fix FORCE_SYNC_ACK missing seq (stale-ACK guard)
- Fix episode lobby readyPeers asymmetry (initiator now included)
- Add extractEpisodeId() parsing S01E01, Season 1 Ep 1, Folge 5, Ep. 3, #42
- Add isDifferentEpisode() guard blocking cross-episode sync commands
- Add sameEpisode() for format-tolerant lobby title matching
- Guard controlled via autoSyncNextEpisode setting
- Reduce reactive lock 1000ms → 300ms
- Fix routeToContent unbounded retry (max 3 attempts)
- Fix server bcrypt.hash failure crashing join flow
- Fix sameEpisode(null, title) returning true
- Fix forceSyncTimeout leak on rapid force sync clicks
- Persist lastSeqBySender across service worker restarts
- Bump version: 1.8.10 → 1.9.0

extension/background.js

@@ -976,6 +976,10 @@ async function routeToContent(action, payload) {
     const actionTimestamp = payload?.actionTimestamp || Date.now();
     const commandSenderId = payload?.senderId || null;
 
+    _routeToContentInternal(tabId, action, payload, actionTimestamp, commandSenderId, 0);
+}
+
+function _routeToContentInternal(tabId, action, payload, actionTimestamp, commandSenderId, retries) {
     chrome.tabs.sendMessage(tabId, { 
         type: 'SERVER_COMMAND',
         action,
@@ -983,12 +987,18 @@ async function routeToContent(action, payload) {
         actionTimestamp,
         commandSenderId
     }).catch(err => {
+        if (retries >= 3) {
+            addLog(`Content Script not responding in tab ${tabId} after ${retries} retries`, 'warn');
+            currentTabId = null;
+            updateBadgeStatus();
+            return;
+        }
         if (err.message.includes('Receiving end does not exist') || err.message.includes('Extension context invalidated')) {
             chrome.scripting.executeScript({
                 target: { tabId },
                 files: ['content.js']
             }).then(() => {
-                setTimeout(() => routeToContent(action, payload), 500);
+                setTimeout(() => _routeToContentInternal(tabId, action, payload, actionTimestamp, commandSenderId, retries + 1), 500);
             }).catch(_err => {
                 addLog(`Auto-reinject failed for tab ${tabId}`, 'warn');
             });

extension/manifest.base.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "KoalaSync",
-  "version": "1.8.10",
+  "version": "1.9.0",
   "description": "Synchronize video playback on YouTube, Netflix, Emby, Jellyfin, and any HTML5 site in real-time with friends.",
   "permissions": [
     "storage",