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/sync/test_secondary_poll.py

@@ -13,7 +13,7 @@ from sqlalchemy.pool import NullPool
 from app.config import get_settings
 from app.db import session_scope
 from app.identity.passwords import hash_password
-from app.models import Account, Mailbox, Message, User
+from app.models import Account, Draft, Mailbox, Message, User
 from app.providers.base import MailboxDelta, RemoteMessage
 from app.sync import engine as sync_engine
 
@@ -97,3 +97,73 @@ async def test_secondary_poll_syncs_special_folders_not_inbox(monkeypatch) -> No
             await cleanup.execute(delete(User).where(User.id == user.id))
         await session.close()
         await engine.dispose()
+
+
+async def test_drafts_poll_reconciles_expunged_rows(monkeypatch) -> None:  # type: ignore[no-untyped-def]
+    """A Drafts poll drops DB rows whose server copy was expunged (phantoms) and
+    un-links a local draft whose mirrored copy vanished."""
+    engine = create_async_engine(get_settings().database_url, poolclass=NullPool)
+    sm = async_sessionmaker(engine, expire_on_commit=False)
+    session = sm()
+    user = User(handle=f"rec{uuid.uuid4().hex[:8]}@test.local", password_hash=hash_password("pw"))
+    session.add(user)
+    await session.flush()
+    account = Account(
+        user_id=user.id,
+        email="me@example.com",
+        imap_config={},
+        smtp_config={},
+        secret_ct=b"",
+        discovery_src="manual",
+    )
+    session.add(account)
+    await session.flush()
+    drafts = Mailbox(account_id=account.id, user_id=user.id, path="DRAFTS", special_use="drafts")
+    session.add(drafts)
+    await session.flush()
+
+    # uid 2 survives on the server; uids 1 and 3 were expunged (phantom DB rows).
+    for uid in (1, 2, 3):
+        session.add(
+            Message(
+                user_id=user.id,
+                account_id=account.id,
+                mailbox_id=drafts.id,
+                uid=uid,
+                internal_date=datetime.now(UTC),
+                blob_sha256="",
+            )
+        )
+    # A local draft still linking the vanished uid 3 must be un-linked (imap_uid -> NULL).
+    linked = Draft(user_id=user.id, account_id=account.id, kind="new", payload={}, imap_uid=3)
+    kept = Draft(user_id=user.id, account_id=account.id, kind="new", payload={}, imap_uid=2)
+    session.add_all([linked, kept])
+    await session.commit()
+
+    class FakeProvider:
+        async def poll(self, mailbox: str, *, last_seen_uid: int, highestmodseq: int | None):  # type: ignore[no-untyped-def]
+            return MailboxDelta([], [], [], None, None)
+
+        async def list_uids(self, mailbox: str) -> set[int]:
+            return {2}  # only uid 2 remains on the server
+
+        async def close(self) -> None:
+            return None
+
+    monkeypatch.setattr(sync_engine, "build_provider", lambda _a: FakeProvider())
+
+    try:
+        await sync_engine._poll_secondary_once(account.id)
+
+        session.expunge_all()
+        remaining = set(
+            await session.scalars(select(Message.uid).where(Message.mailbox_id == drafts.id))
+        )
+        assert remaining == {2}  # phantoms 1 and 3 removed
+        assert (await session.get(Draft, linked.id)).imap_uid is None  # un-linked
+        assert (await session.get(Draft, kept.id)).imap_uid == 2  # untouched
+    finally:
+        async with session_scope() as cleanup:
+            await cleanup.execute(delete(User).where(User.id == user.id))
+        await session.close()
+        await engine.dispose()