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/app/outbox/service.py

@@ -9,7 +9,7 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.config import get_settings
-from app.models import Account, Draft, Outbox
+from app.models import Account, Draft, Mailbox, Message, Outbox
 from app.outbox.schemas import DraftIn
 
 
@@ -17,6 +17,29 @@ class DraftError(Exception):
     """Draft could not be created/updated (e.g. account not owned)."""
 
 
+async def delete_mirrored_draft_row(
+    session: AsyncSession, *, account_id: uuid.UUID, imap_uid: int
+) -> None:
+    """Delete the DB row for a draft that was mirrored into the IMAP Drafts folder.
+
+    The server copy is expunged separately (send_job / remove_imap_draft_job).
+    Without also dropping this row the draft resurfaces in ``list_remote_drafts``
+    as an "other client" draft once its local ``drafts`` row is gone — until the
+    next Drafts poll would catch the expunge. Used on both send and discard.
+    """
+    mirror = await session.scalar(
+        select(Message)
+        .join(Mailbox, Mailbox.id == Message.mailbox_id)
+        .where(
+            Message.account_id == account_id,
+            Message.uid == imap_uid,
+            Mailbox.special_use == "drafts",
+        )
+    )
+    if mirror is not None:
+        await session.delete(mirror)
+
+
 async def upsert_draft(
     session: AsyncSession, *, user_id: uuid.UUID, body: DraftIn, draft_id: uuid.UUID | None
 ) -> Draft: