Two-way draft sync, signatures, sent/bcc fixes, and mail-list UI

Backend
- Sent copies: persist locally on send + periodic multi-folder CONDSTORE poll
  (Sent/Archive/Trash/Junk) so they thread and show without an IDLE-only INBOX.
- Bcc: transmitted copy omits Bcc, Sent copy keeps it; store/display bcc_addr.
- Drafts: mirror local drafts to the IMAP Drafts folder (append/replace/expunge);
  inbound sync of foreign drafts (un-threaded) with adopt-to-edit + dedup by UID.
- Per-user storage quota (5 GiB default) and manual "sync all folders" action.
- Account editing (display/color/server/password) and per-account HTML signature.
- Account view scoped to that account's inbox; new migrations 0006–0009.

Frontend
- Mail-list pagination, folder filters (All/Unread/Pinned), sort toggle, refresh.
- Aligned + widened mail-list margins; reading-pane bars fixed height.
- Rich-text composer: color palette, highlight, image; attachments; expand/pop-out.
- Signatures: auto-insert for new mail, replace on From change, reply insert.
- Restore/Delete actions per folder; drafts view merges local + remote, date-sorted.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/workers/worker.py

@@ -10,6 +10,7 @@ import uuid
 from typing import Any
 
 from app.config import get_settings
+from app.outbox.draft_sync import push_draft_to_imap_job, remove_imap_draft_job
 from app.outbox.jobs import send_job
 from app.queue import redis_settings as arq_redis_settings
 from app.sync.actions import (
@@ -18,7 +19,7 @@ from app.sync.actions import (
     move_thread_to_folder_job,
     push_flags_job,
 )
-from app.sync.engine import bootstrap_and_backfill
+from app.sync.engine import bootstrap_and_backfill, refresh_account_job
 
 logger = logging.getLogger(__name__)
 
@@ -60,6 +61,9 @@ class WorkerSettings:
         move_thread_to_folder_job,
         delete_thread_job,
         send_job,
+        push_draft_to_imap_job,
+        remove_imap_draft_job,
+        refresh_account_job,
     ]
     on_startup = on_startup
     on_shutdown = on_shutdown