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/dashboard/conversations.test.tsx

@@ -20,6 +20,8 @@ interface ChatFixtureOptions {
   lastMessageSnippet?: string;
   hasReceivedImages?: boolean;
   sellerDetected?: boolean;
+  automationStatus?: 'active' | 'image-received' | 'human-required' | 'boundary' | 'user-overridden';
+  automationHandoffReason?: string;
 }
 
 function chatFixture(options: ChatFixtureOptions) {
@@ -34,6 +36,10 @@ function chatFixture(options: ChatFixtureOptions) {
     unread: options.unread ?? false,
     ...(options.hasReceivedImages === undefined ? {} : { hasReceivedImages: options.hasReceivedImages }),
     ...(options.sellerDetected === undefined ? {} : { sellerDetected: options.sellerDetected }),
+    ...(options.automationStatus === undefined ? {} : { automationStatus: options.automationStatus }),
+    ...(options.automationHandoffReason === undefined
+      ? {}
+      : { automationHandoffReason: options.automationHandoffReason }),
   };
 }
 
@@ -269,6 +275,30 @@ describe('ConversationsPage', () => {
     expect(screen.getByRole('img', { name: 'Image received from u/alice' })).not.toHaveClass('is-blurred');
   });
 
+  it('marks and filters conversations that are being replied to by hand', async () => {
+    const manual = chatFixture({
+      username: 'alice',
+      roomId: 'room-alice',
+      isFromUs: true,
+      automationStatus: 'user-overridden',
+      automationHandoffReason: 'A manual reply was sent in this conversation.',
+    });
+    const automated = chatFixture({ username: 'bob', roomId: 'room-bob', automationStatus: 'active' });
+    server.use(http.get('/api/conversations', () => HttpResponse.json([manual, automated])));
+    const user = userEvent.setup();
+    renderConversations();
+
+    await screen.findByRole('button', { name: /u\/alice/ });
+    expect(screen.getByText('Manual', { selector: '.conversation-chip' })).toHaveAttribute(
+      'title',
+      'Manual — you replied — A manual reply was sent in this conversation.',
+    );
+
+    await user.click(screen.getByRole('button', { name: 'Manual, 1' }));
+    expect(screen.getByRole('button', { name: /u\/alice/ })).toBeInTheDocument();
+    expect(screen.queryByRole('button', { name: /u\/bob/ })).not.toBeInTheDocument();
+  });
+
   it('turns a suggestion into an editable draft and confirms sending without losing failed input', async () => {
     installConversationList();
     let sendRequests = 0;