fix: address PR Agent review findings across 6 files

Restrict PR Agent workflow to trusted collaborators on PR comments only,
fix UTF-8 byte counting in gallery-pack, correct portrait-to-landscape
fallback orientation, track inserted freeform beats in visitedBeatIds,
allow clearing stored TTS key, and guard empty-string fuzzy match in
style selector.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

components/SettingsModal.tsx

@@ -100,10 +100,9 @@ export function SettingsModal({
       const presetId = keyType === "payg" ? PAYG_PRESET_ID : regionId;
       writeStoredTtsConfig({ presetId, apiKey: key });
       ttsConfigured = true;
-    } else if (!ttsAlreadyConfigured) {
-      ttsConfigured = false;
     } else {
-      ttsConfigured = true;
+      clearStoredTtsConfig();
+      ttsConfigured = false;
     }
 
     onSaved({ ttsConfigured, playerName: name, visionClickEnabled: visionClick });