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/media-sync-auth.test.ts

@@ -20,4 +20,55 @@ describe('MediaSyncService account authentication gate', () => {
     expect(chat.refreshTopChats).not.toHaveBeenCalled();
     expect(chat.fetchAllMessages).not.toHaveBeenCalled();
   });
+
+  it('reports the actual number of rooms changed by an incremental sync', async () => {
+    const chat = {
+      refreshTopChats: vi.fn().mockResolvedValue(3),
+      fetchAllMessages: vi.fn(),
+    };
+    const service = new MediaSyncService(
+      chat as never,
+      createMockLogger(),
+      30 * 60 * 1000,
+      { isFullyAuthenticated: () => true },
+    );
+
+    await expect(service.triggerSync()).resolves.toBe(true);
+    expect(service.getStatus().lastSyncChats).toBe(3);
+  });
+
+  it('requires a complete historical backfill for a full media sync', async () => {
+    const chat = {
+      refreshTopChats: vi.fn(),
+      fetchAllMessages: vi.fn().mockResolvedValue([]),
+    };
+    const service = new MediaSyncService(
+      chat as never,
+      createMockLogger(),
+      30 * 60 * 1000,
+      { isFullyAuthenticated: () => true },
+    );
+
+    await service.triggerSync(true);
+    expect(chat.fetchAllMessages).toHaveBeenCalledWith({ requireComplete: true });
+  });
+
+  it('returns failure and preserves the operator-visible error when sync work is incomplete', async () => {
+    const chat = {
+      refreshTopChats: vi.fn().mockRejectedValue(new Error('media history incomplete')),
+      fetchAllMessages: vi.fn(),
+    };
+    const service = new MediaSyncService(
+      chat as never,
+      createMockLogger(),
+      30 * 60 * 1000,
+      { isFullyAuthenticated: () => true },
+    );
+
+    await expect(service.triggerSync()).resolves.toBe(false);
+    expect(service.getStatus()).toMatchObject({
+      lastSyncAt: null,
+      lastError: 'media history incomplete',
+    });
+  });
 });