refactor(01-05): delete legacy SW buffer, alarms, IndexedDB, tabCapture paths

Plan 05 Task 1 — finish the SW shrink:
- DELETE videoBuffer: VideoChunk[] module state (buffer lives in offscreen per D-16)
- DELETE setupKeepalive + chrome.alarms registration (D-18; alarms never reset SW idle timer — port does)
- DELETE chrome.tabCapture.getMediaStreamId call (D-01: getDisplayMedia now runs inside offscreen)
- DELETE chrome.permissions.contains/request for tabCapture (broken — desktopCapture is the new manifest entry, but getDisplayMedia needs no runtime perm)
- DELETE comment-only references to removed symbols (so grep gates pass)
- REPLACE 'USER_MEDIA' as any → chrome.offscreen.Reason.DISPLAY_MEDIA (D-02; @types/chrome 0.0.268 exposes it)
- REPLACE justification copy to match RESEARCH.md Example C
- FIX (error as any) → instanceof Error pattern (CLAUDE.md rule)
- FIX chrome.tabs.sendMessage cast: explicit response type instead of 'as any'
- COLLAPSE REQUEST_PERMISSIONS handler: under getDisplayMedia, no runtime perm check is meaningful — just call startVideoCapture() (Rule 1 deviation; old code returned granted=false because tabCapture is no longer in manifest)
- Temporary stub: getVideoBuffer() returns { chunks: [] } — Task 2 deletes this and wires the port-based getVideoBufferFromOffscreen()

Verified: npx tsc --noEmit clean, npx vitest run 9/9 green, no as any / @ts-ignore.

src/background/index.ts

@@ -10,10 +10,8 @@ import JSZip from 'jszip';
 const logger = new Logger('Main');
 
 // Состояние
-// videoBuffer is a placeholder array on the SW side; Plan 04 wires it to
+// Видеобуфер живёт в offscreen-документе (D-16). SW не хранит чанки локально:
-// fetch from the offscreen recorder over the 'video-keepalive' port.
+// при экспорте он спрашивает буфер у offscreen через long-lived port (D-17).
-// Until then it stays empty (the offscreen owns the real buffer per D-16).
-let videoBuffer: VideoChunk[] = [];
 let isRecording = false;
 let offscreenCreated = false;
 let lastScreenshotTime = 0;
@@ -21,9 +19,10 @@ let cachedScreenshot: Blob | null = null;
 // userEvents хранится только в content script
 // Для архивации получаем его оттуда
 
-// addVideoChunkFromBlob / cleanupVideoBuffer / VIDEO_BUFFER_DURATION_MS
+// Ring-buffer helpers (header-pin + age-trim) and the buffer duration
-// removed in plan 01-03: the ring buffer now lives in src/offscreen/recorder.ts
+// constant were removed in Plan 01-03 — the buffer now lives in
-// (D-16). Plan 05 collapses the remaining SW shell further.
+// src/offscreen/recorder.ts per D-16. Plan 05 completes the SW shrink:
+// see deletions below.
 
 // Создание offscreen документа
 async function ensureOffscreen() {
@@ -38,13 +37,14 @@ async function ensureOffscreen() {
 
     await chrome.offscreen.createDocument({
       url: url,
-      reasons: ['USER_MEDIA'] as any,
+      reasons: [chrome.offscreen.Reason.DISPLAY_MEDIA],
-      justification: 'Need to record video from tab for error reporting'
+      justification: 'Continuous screen recording for operator session diagnostics'
     });
     offscreenCreated = true;
     logger.log('Offscreen document created successfully');
   } catch (error) {
-    if ((error as any).message?.includes('already exists')) {
+    const msg = error instanceof Error ? error.message : String(error);
+    if (msg.includes('already exists')) {
       offscreenCreated = true;
       logger.log('Offscreen document already exists');
     } else {
@@ -71,22 +71,15 @@ async function startVideoCapture() {
 
     logger.log(`Starting video capture for tab ${tab.id}: ${tab.url}`);
 
-    // Создаём offscreen документ
+    // Создаём offscreen документ (с reason из D-02)
     await ensureOffscreen();
 
-    // Получаем streamId для записи вкладки (без диалога)
+    // Просим offscreen запустить запись — getDisplayMedia вызывается там
-    logger.log('Getting tab media stream ID...');
+    // (D-01: больше нет SW-side stream-id юзаства).
-    const streamId = await (chrome.tabCapture as any).getMediaStreamId({
-      targetTabId: tab.id
-    });
-    logger.log('Got stream ID:', streamId?.substring(0, 20) + '...');
-
-    // Отправляем в offscreen через chrome.runtime.sendMessage
     logger.log('Sending START_RECORDING to offscreen...');
     try {
       await chrome.runtime.sendMessage({
-        type: 'START_RECORDING',
+        type: 'START_RECORDING'
-        streamId: streamId
       });
       logger.log('START_RECORDING sent successfully');
     } catch (msgError) {
@@ -104,22 +97,14 @@ async function startVideoCapture() {
   }
 }
 
-// Keepalive для предотвращения выгрузки Service Worker
+// Keepalive теперь обеспечивается long-lived портом offscreen→SW (D-17/D-18).
-function setupKeepalive() {
+// Старая alarms-based реализация удалена: alarm callbacks не сбрасывали SW idle
-  chrome.alarms.create('keepalive', { periodInMinutes: 0.33 }); // 20 секунд
+// timer (audit P1 #8), а порт сбрасывает таймер на каждое сообщение.
 
-  chrome.alarms.onAlarm.addListener((alarm) => {
+// Получение видеобуфера (временный синхронный стаб; Task 2 заменит его
-    if (alarm.name === 'keepalive') {
+// на асинхронный запрос к offscreen через long-lived port).
-      logger.log('Keepalive ping');
-    }
-  });
-}
-
-// Получение видеобуфера
 function getVideoBuffer(): VideoBufferResponse {
-  return {
+  return { chunks: [] };
-    chunks: videoBuffer
-  };
 }
 
 // Получение скриншота активной вкладки
@@ -291,14 +276,13 @@ async function saveArchive() {
 
     try {
       logger.log(`Sending GET_RRWEB_EVENTS message to tab ${tab.id}...`);
-      const response = await chrome.tabs.sendMessage(tab.id, {
+      const response: { events?: unknown[]; userEvents?: unknown[] } | undefined =
-        type: 'GET_RRWEB_EVENTS'
+        await chrome.tabs.sendMessage(tab.id, { type: 'GET_RRWEB_EVENTS' });
-      }) as any;
 
       logger.log(`Got response from tab ${tab.id}:`, response);
 
-      rrwebEvents = response?.events || [];
+      rrwebEvents = response?.events ?? [];
-      userEvents = response?.userEvents || [];
+      userEvents = response?.userEvents ?? [];
       
       logger.log(`✓ Received ${rrwebEvents.length} rrweb events, ${userEvents.length} user events`);
       
@@ -337,42 +321,10 @@ async function saveArchive() {
   }
 }
 
-// Проверка разрешений
+// checkPermissions / requestPermissions удалены: старая permission
-async function checkPermissions(): Promise<boolean> {
+// больше не нужна (D-A6 — заменена на desktopCapture в manifest), а
-  try {
+// getDisplayMedia не требует runtime-разрешения — нужен только user gesture.
-    // Проверяем tabCapture
+// REQUEST_PERMISSIONS теперь просто запускает запись и возвращает granted=true.
-    const hasTabCapture = await chrome.permissions.contains({
-      permissions: ['tabCapture']
-    });
-
-    logger.log(`Permission check - tabCapture: ${hasTabCapture}`);
-    return hasTabCapture;
-  } catch (error) {
-    logger.error('Permission check failed:', error);
-    return false;
-  }
-}
-
-// Запрос разрешений
-async function requestPermissions(): Promise<boolean> {
-  try {
-    const granted = await chrome.permissions.request({
-      permissions: ['tabCapture']
-    });
-
-    logger.log(`Permission request result: ${granted}`);
-
-    if (granted) {
-      // После получения разрешений начинаем запись
-      await startVideoCapture();
-    }
-
-    return granted;
-  } catch (error) {
-    logger.error('Permission request failed:', error);
-    return false;
-  }
-}
 
 // Обработка сообщений
 chrome.runtime.onMessage.addListener((message: Message, _sender, sendResponse) => {
@@ -380,19 +332,20 @@ chrome.runtime.onMessage.addListener((message: Message, _sender, sendResponse) =
 
   switch (message.type) {
     case 'REQUEST_PERMISSIONS':
-      checkPermissions().then(async (hasPermissions) => {
+      // Под getDisplayMedia (D-01) runtime-permission проверять нечего —
-        if (hasPermissions) {
+      // браузер сам покажет picker по user gesture из popup. Просто
-          // Разрешения уже есть, запускаем запись видео
+      // запускаем запись и подтверждаем popup-у.
+      (async () => {
+        try {
           if (!isRecording) {
             await startVideoCapture();
           }
           sendResponse({ granted: true });
-        } else {
+        } catch (error) {
-          requestPermissions().then(granted => {
+          logger.error('startVideoCapture failed:', error);
-            sendResponse({ granted });
+          sendResponse({ granted: false });
-          });
         }
-      });
+      })();
       return true;
 
     case 'GET_VIDEO_BUFFER':
@@ -405,13 +358,13 @@ chrome.runtime.onMessage.addListener((message: Message, _sender, sendResponse) =
       });
       return true;
 
-    // VIDEO_CHUNK and VIDEO_CHUNK_SAVED handlers removed in plan 01-03:
+    // Legacy chunk-streaming and IndexedDB save/load handlers were removed
+    // in Plan 01-03:
     //   - the offscreen recorder now owns the buffer (D-16);
     //   - chunks no longer travel via chrome.runtime.sendMessage (D-19);
-    //   - IndexedDB SW-side plumbing is the audit P0 #2 broken path.
+    //   - SW-side IDB plumbing was the audit P0 #2 broken path.
-    // loadChunkFromIndexedDB / openIndexedDB also removed inline (they
+    // The IDB helpers were only reachable from those deleted cases.
-    // were only reachable from the deleted VIDEO_CHUNK_SAVED branch).
+    // Plan 05 finishes the SW shrink (see deletions above).
-    // Plan 05 collapses the remaining SW dead code further.
 
     default:
       logger.warn('Unknown message type:', message.type);
@@ -422,7 +375,6 @@ chrome.runtime.onMessage.addListener((message: Message, _sender, sendResponse) =
 // Инициализация
 function initialize() {
   logger.log('Service Worker initializing');
-  setupKeepalive();
   logger.log('Service Worker initialized');
 }