Sender avatars, PDF password preview, contacts autosave, account-view + Trash/Spam auto-purge, UI polish

Sender avatars (privacy-safe, server-fetched, cached):
- New GET /api/avatar resolves Gravatar (d=404) then the sender domain's favicon
  under the SSRF guard, Redis-cached (hit+miss); gated by SENDER_AVATARS_ENABLED.
  GuardedResponse gains raw bytes. Shown in the mail list, reading pane, People
  panel, and Contacts (overlay that falls back to initials on a miss).

PDF preview:
- Password-protected PDFs now prompt in-place and retry (pdf.js PasswordException),
  with a clear error for other load failures instead of a blank overlay. The
  password is remembered per attachment until the thread is left; clicking the
  field no longer dismisses the overlay.

Contacts:
- Autosave reply recipients: message.sent now carries to/cc (name+email); the
  contacts plugin subscribes and adds any non-contact recipients to the Autosaved
  group. Contact avatars show the gravatar/favicon via /api/avatar.

Mail views / retention:
- Clicking an account shows all its mail except Trash/Spam (was inbox-only).
- Daily cron autopurge_trash_spam permanently deletes Trash/Spam older than
  TRASH_RETENTION_DAYS (default 30; 0 disables) — server EXPUNGE + local rows.

UI polish:
- Ultimo signet logo in the Mail/Calendar/Contacts sidebar header and collapsed
  rail; consistent 11px top margin and vertically-aligned header row across states
  (fixed-size flex icon buttons); SVG favicon on the browser tab.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01U72FZiF1W1pb8XxyWBTREA

backend/workers/run.py

@@ -21,13 +21,19 @@ import logging
 import signal
 from typing import Any
 
+from arq import cron
 from arq.worker import Worker
 
 from app.config import get_settings
 from app.queue import QUEUE_BULK, QUEUE_INTERACTIVE, redis_settings
+from app.sync.actions import autopurge_trash_spam
 from app.sync.coordinator import SyncCoordinator
 from workers.worker import BULK_FUNCTIONS, INTERACTIVE_FUNCTIONS
 
+# Core scheduled jobs. Daily Trash/Spam retention purge at 03:17 (off-peak, and a
+# minute that won't collide with typical top-of-hour crons).
+_CORE_CRON_JOBS = [cron(autopurge_trash_spam, hour=3, minute=17)]
+
 logger = logging.getLogger(__name__)
 
 _SHUTDOWN_DRAIN_S = 10.0  # §7: release leases + drain within this budget
@@ -67,7 +73,7 @@ def build_arq_workers(role: str) -> list[Worker]:
             QUEUE_INTERACTIVE,
             s.interactive_concurrency,
             120,
-            cron_jobs=plugin_cron_jobs(),
+            cron_jobs=[*_CORE_CRON_JOBS, *plugin_cron_jobs()],
         ),
         _worker(BULK_FUNCTIONS, QUEUE_BULK, s.bulk_concurrency, 3600),
     ]