feat: recover missing conversations, fix media attachment, add manual inbox tab

Missing conversations: recipient Reddit accounts that are deleted or suspended
left conversations unaccounted for. A new RecipientAccountStatusService polls
Reddit for the users behind cached conversations and records their account
status durably, with progressive backfill and delta-media fixes in ChatService
so history and images are no longer dropped mid-sync.

Media: attachMedia now surfaces download failures as MediaAttachmentError so the
sync cursor can be retried instead of silently losing an image, recognizes image
bytes when Matrix returns a generic content type, and keeps separate gallery
occurrences when the same asset appears in more than one event.

Manual inbox tab: the conversations list now carries the reply-loop status, so
the inbox can separate conversations the operator is driving by hand from the
ones automation is still handling. A Manual filter pill and a per-row chip
explain why each conversation was handed over.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/chat-service-delta-media.test.ts

@@ -198,4 +198,81 @@ describe('ChatService delta sync — media attachment', () => {
     const svc = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache, undefined, undefined, authenticatedAccountAuth);
     await expect(svc.getActiveChats()).resolves.toBeDefined();
   });
+
+  it('backfills the room when Matrix marks a delta timeline as limited', async () => {
+    const logger = createMockLogger();
+    const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'chat-limited-delta-media-'));
+    try {
+      const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });
+      matrix.sync = vi.fn(async () => ({
+        next_batch: 's2',
+        rooms: { join: { '!room1:example.test': {
+          timeline: {
+            limited: true,
+            prev_batch: 'gap-token',
+            events: [],
+          },
+        } } },
+      })) as typeof matrix.sync;
+      matrix.getRoomMessages = vi.fn(async () => ({
+        start: 'latest',
+        chunk: [{
+          event_id: '$missed-image', type: 'm.room.message', sender: '@t2_abc:example.test',
+          origin_server_ts: 1_000,
+          content: { msgtype: 'm.image', info: { thumbnail_url: 'mxc://example.test/missed' } },
+        }],
+      }));
+
+      const media = new MediaService(buildDownloader(), logger, tmpDir);
+      const svc = new ChatService(
+        matrix, logger, undefined, media, undefined, undefined,
+        new ChatCache(logger, path.join(tmpDir, 'chat-cache.json')),
+        undefined, undefined, authenticatedAccountAuth,
+      );
+
+      await expect(svc.refreshTopChats()).resolves.toBe(1);
+      expect(matrix.getRoomMessages).toHaveBeenCalledWith(
+        '!room1:example.test', { from: undefined, limit: 100, dir: 'b' },
+      );
+      expect(await media.getMediaItems()).toEqual([
+        expect.objectContaining({ originalUrl: 'mxc://example.test/missed' }),
+      ]);
+    } finally {
+      await fs.rm(tmpDir, { recursive: true, force: true });
+    }
+  });
+
+  it('does not persist the next delta cursor when a media download fails', async () => {
+    const logger = createMockLogger();
+    const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'chat-media-retry-cursor-'));
+    const cacheFile = path.join(tmpDir, 'chat-cache.json');
+    try {
+      await fs.writeFile(cacheFile, JSON.stringify({
+        version: 1, savedAt: 1, chats: [], nextBatch: 's1',
+        lastFullSyncAt: 1, lastDeltaSyncAt: 1, cooldown: null,
+      }));
+      const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });
+      matrix.sync = vi.fn(async () => ({
+        next_batch: 's2',
+        rooms: { join: { '!room1:example.test': { timeline: { events: [{
+          event_id: '$image', type: 'm.room.message', sender: '@t2_abc:example.test',
+          origin_server_ts: 1_000, content: { msgtype: 'm.image', url: 'mxc://example.test/fails' },
+        }] } } } },
+      })) as typeof matrix.sync;
+      const media = new MediaService({ fetch: vi.fn().mockResolvedValue(null) }, logger, tmpDir);
+      const cache = new ChatCache(logger, cacheFile);
+      const svc = new ChatService(
+        matrix, logger, undefined, media, undefined, undefined, cache,
+        undefined, undefined, authenticatedAccountAuth,
+      );
+      await svc.loadCache();
+
+      await expect(svc.refreshTopChats()).rejects.toThrow('Failed to retrieve');
+
+      const persisted = JSON.parse(await fs.readFile(cacheFile, 'utf-8')) as { nextBatch: string };
+      expect(persisted.nextBatch).toBe('s1');
+    } finally {
+      await fs.rm(tmpDir, { recursive: true, force: true });
+    }
+  });
 });