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/database.test.ts

@@ -107,13 +107,14 @@ describe('Database Client', () => {
         .prepare("SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%'")
         .all() as { name: string }[];
       // Existing domain/config tables plus account, conversation, sync and media ownership stores.
-      expect(tables.length).toBe(21);
+      expect(tables.length).toBe(22);
       expect(tables.map((table) => table.name)).toEqual(expect.arrayContaining([
         'candidate_queue',
         'runtime_state',
         'media_library_assets',
         'media_library_sends',
         'conversation_read_state',
+        'reddit_recipient_account_status',
       ]));
     });