mail UX: restore-to-folder, draft/attachment fixes, printing, sidebar collapse

Backend:
- Restore returns each message to its original folder (e.g. Sent/Archive) instead
  of always the Inbox: new messages.restore_mailbox_id (migration 0010) +
  restore_thread_job.
- Drafts: expunge reconciliation for the Drafts poll (provider.list_uids /
  _reconcile_drafts) clears phantom "remote" drafts; send + discard drop the
  mirrored DB row; adopting a remote draft carries its real attachments into the
  compose flow.
- Thread detail/list are folder-aware: individually trashed/spam messages are
  hidden outside their folder, Trash/Spam show only their own messages, and the
  mail-list message count matches the view.

Frontend:
- Thread reading panel: fix newest-first card overlap/spacing (expand-all and
  single expand), hide Reply/Forward on trashed messages, close the Actions menu
  on message-body (iframe) clicks, scroll to the inline composer, and prompt
  Save draft / Discard on the X close.
- Composer: remount when switching drafts, dirty-tracking to stop duplicate IMAP
  mirrors, and close the From/More dropdowns on outside click.
- Sidebar: collapse/expand toggle (icons-only ~60px rail) and a log-out icon on
  Sign out.
- Mail-standard printing in a new window with reliable page margins (lib/print.ts).

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

backend/tests/mail/test_actions.py

@@ -225,14 +225,20 @@ async def test_archive_unknown_thread_404(ctx: Ctx) -> None:
     assert ctx.enqueued == []
 
 
-async def test_restore_thread_enqueues_move_to_inbox(ctx: Ctx) -> None:
+async def test_restore_thread_enqueues_restore_job(ctx: Ctx) -> None:
     resp = await ctx.client.post(f"/api/threads/{ctx.thread_id}/restore", headers=_hdr())
     assert resp.status_code == 200
     assert ctx.enqueued == [
-        ("move_thread_to_folder_job", str(ctx.thread_id), "inbox"),
+        ("restore_thread_job", str(ctx.thread_id)),
     ]
 
 
+async def test_restore_unknown_thread_404(ctx: Ctx) -> None:
+    resp = await ctx.client.post(f"/api/threads/{uuid.uuid4()}/restore", headers=_hdr())
+    assert resp.status_code == 404
+    assert ctx.enqueued == []
+
+
 async def test_delete_thread_enqueues_permanent_delete(ctx: Ctx) -> None:
     resp = await ctx.client.post(f"/api/threads/{ctx.thread_id}/delete", headers=_hdr())
     assert resp.status_code == 200