Gmail label sync + no-dup backfill, live label/UI updates, account-delete cleanup, Sync-SPAM toggle, sidebar logo

Gmail sync (SPEC: Gmail sync):
- Provider fetches X-GM-LABELS when X-GM-EXT-1 is advertised; parses custom labels
  (system labels dropped, mUTF-7 decoded) onto RemoteMessage.
- Engine syncs only system folders + All Mail for Gmail, skips every label folder,
  and dedupes the All Mail pass by Message-ID — kills the INBOX/All-Mail duplication.
- Custom labels ride the message.new event; the labels plugin subscribes and maps
  them to chips as "<name> [Gmail]" (per-message + thread aggregate + known set),
  so labels fill in gradually with the sync window. Non-ASCII labels decode right.

Labels self-healing (message-driven reconcile):
- Per-message keys are the source of truth; t: aggregates and _labels are derived.
  Reconcile drops labels of deleted messages, regroups survivors by their current
  thread (fixing JWZ thread merges), rewrites changed t: keys, and rebuilds _labels
  from live messages — keeping user labels, dropping orphaned Gmail ones.
- New SDK reads: sdk.threads.existing / sdk.messages.threads_of. Sidebar refreshes
  live via a plugin.labels.changed WS event on new labels.

Account deletion: prune threads left empty after the cascade (they were user-scoped,
so only messages cascaded) + de-list the account from surviving cross-account threads.

Sync SPAM: opt-in per-account sync_spam (migration 0015, default off) — the engine
skips the Junk folder in backfill and poll unless enabled; wizard checkbox added.

Robustness / UX:
- WebSocket auto-reconnects with backoff and resyncs on (re)connect, and account
  add/delete invalidates threads/labels — no more hard refresh for live updates.
- Backfill banner + sidebar ring also require done < total, so a completed account
  can't leave a stuck "X of X".
- Scrub lone UTF-16 surrogates from parsed headers/bodies so bad messages no longer
  crash the backfill on Postgres text/JSONB.
- Ultimo signet logo in the Mail/Calendar/Contacts sidebar header (and at the top of
  the collapsed rail), via the shared plugin-ui.css + MailLayout.

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

backend/tests/accounts/test_account_api.py

@@ -19,7 +19,7 @@ from app.config import get_settings
 from app.identity.passwords import hash_password
 from app.identity.sessions import create_session
 from app.main import create_app
-from app.models import Account, User
+from app.models import Account, Thread, User
 
 CSRF = "test-csrf-token"
 GOOD_CFG = {
@@ -281,3 +281,46 @@ async def test_delete_account(ctx: Ctx, monkeypatch) -> None:  # type: ignore[no
 
     gone = await ctx.session.scalar(select(Account).where(Account.id == uuid.UUID(account_id)))
     assert gone is None
+
+
+async def test_delete_account_prunes_orphaned_threads(ctx: Ctx, monkeypatch) -> None:  # type: ignore[no-untyped-def]
+    """Deleting an account removes threads left with no messages (else the unified
+    list / label views show empty rows that can't be opened)."""
+    import datetime as dt
+
+    async def fake_test(**_kw: object) -> None:
+        return None
+
+    class FakePool:
+        async def enqueue_job(self, name: str, arg: str, **kwargs: object) -> None:
+            return None
+
+    async def fake_pool() -> FakePool:
+        return FakePool()
+
+    monkeypatch.setattr(accounts_api, "test_account", fake_test)
+    monkeypatch.setattr(app_queue, "get_arq_pool", fake_pool)
+
+    created = await ctx.client.post(
+        "/api/accounts",
+        json={**GOOD_CFG, "email": "orphan@example.com", "password": "secret"},
+        headers=_hdr(),
+    )
+    account_id = uuid.UUID(created.json()["id"])
+    # An empty thread tagged to this account (message-less, as after a cascade delete).
+    thread_id = uuid.uuid4()
+    ctx.session.add(
+        Thread(
+            id=thread_id,
+            user_id=ctx.user_id,
+            subject_norm="orphan",
+            last_message_at=dt.datetime.now(dt.UTC),
+            account_ids=[account_id],
+        )
+    )
+    await ctx.session.commit()
+    ctx.session.expunge_all()  # force the assertion query to hit the DB
+
+    resp = await ctx.client.request("DELETE", f"/api/accounts/{account_id}", headers=_hdr())
+    assert resp.status_code == 200
+    assert await ctx.session.scalar(select(Thread).where(Thread.id == thread_id)) is None

backend/tests/indexer/test_mime.py

@@ -49,6 +49,17 @@ def test_parse_basic_headers_and_body() -> None:
     assert parsed.snippet == "plain body"
 
 
+def test_undecodable_header_bytes_scrubbed_to_valid_utf8() -> None:
+    # A raw 8-bit byte the parser can't decode surfaces as a lone surrogate; it must
+    # be scrubbed so the value is valid UTF-8 for Postgres text/JSONB storage.
+    raw = _build(subject="Fakt\udce9ra", from_addr="B\udce9ta <b@example.com>")
+    parsed = parse_message(raw)
+    parsed.subject.encode("utf-8")  # would raise on a lone surrogate
+    parsed.from_addr[0]["name"].encode("utf-8")
+    assert "\udce9" not in parsed.subject
+    assert "�" in parsed.subject
+
+
 def test_references_include_in_reply_to_in_order() -> None:
     parsed = parse_message(_build(references="<a@x.com> <b@x.com>", in_reply_to="<b@x.com>"))
     # References first, then In-Reply-To, deduped

backend/tests/providers/test_parsing.py

@@ -37,6 +37,17 @@ def test_parse_list_plain_folder_has_no_special_use() -> None:
     assert parsed.special_use is None
 
 
+def test_parse_list_skips_noselect_containers() -> None:
+    # \Noselect / \NonExistent hierarchy nodes can't be SELECTed (Gmail's [Gmail]
+    # root, a parent label like "Serial numbers " that only groups children).
+    assert parse_list_line(rb'(\HasChildren \Noselect) "/" "[Gmail]"') is None
+    assert parse_list_line(rb'(\HasChildren \Noselect) "/" "Serial numbers "') is None
+    assert parse_list_line(rb'(\NonExistent \HasChildren) "/" "Parent"') is None
+    # A selectable child of that container is still parsed.
+    child = parse_list_line(rb'(\HasNoChildren) "/" "Serial numbers / licencje"')
+    assert child is not None and child.path == "Serial numbers / licencje"
+
+
 def test_parse_list_utf7_name() -> None:
     # Modified UTF-7: "&AOk-" decodes to "é" -> folder "Réponses"
     parsed = parse_list_line(rb'(\HasNoChildren) "/" "R&AOk-ponses"')
@@ -44,6 +55,35 @@ def test_parse_list_utf7_name() -> None:
     assert parsed.path == "Réponses"
 
 
+def test_parse_gm_labels() -> None:
+    from app.providers.imap_smtp.parsing import parse_gm_labels
+
+    # System labels (backslash-prefixed) are dropped; custom labels kept + decoded.
+    header = rb'1 FETCH (UID 5 X-GM-LABELS (\Inbox \Important "Konkurs" "Projekty/2026") FLAGS ())'
+    assert parse_gm_labels(header) == ("Konkurs", "Projekty/2026")
+    # Unquoted single-word custom label.
+    assert parse_gm_labels(rb"1 FETCH (UID 5 X-GM-LABELS (\Sent PUP))") == ("PUP",)
+    # Modified UTF-7 decoding of a non-ASCII label ("Zg&AUI-oszenia" -> "Zgłoszenia").
+    assert parse_gm_labels(rb'1 FETCH (X-GM-LABELS ("Zg&AUI-oszenia"))') == ("Zgłoszenia",)
+    # No X-GM-LABELS at all.
+    assert parse_gm_labels(rb"1 FETCH (UID 5 FLAGS (\Seen))") == ()
+    # Only system labels -> empty.
+    assert parse_gm_labels(rb"1 FETCH (X-GM-LABELS (\Inbox \Starred))") == ()
+
+
+def test_parse_fetch_lines_carries_gm_labels() -> None:
+    lines = [
+        rb'1 FETCH (UID 9 X-GM-LABELS (\Inbox "Work") FLAGS (\Seen) '
+        rb'INTERNALDATE "27-May-2026 19:08:09 +0200" RFC822.SIZE 3 BODY[] {3}',
+        b"abc",
+        b")",
+    ]
+    out = parse_fetch_lines(lines)
+    assert len(out) == 1
+    assert out[0].gmail_labels == ("Work",)
+    assert out[0].raw == b"abc"
+
+
 def test_parse_internaldate() -> None:
     dt = parse_internaldate("27-May-2026 19:08:09 +0200")
     assert dt == datetime.fromisoformat("2026-05-27T19:08:09+02:00")

backend/tests/sync/test_backfill_window.py

@@ -31,6 +31,8 @@ def _raw(mid: str) -> bytes:
 
 
 class _FakeProvider:
+    gmail_labels_supported = False
+
     def __init__(self) -> None:
         self.backfill_calls: list[tuple[str, date | None, date | None]] = []
         self.count_calls: list[tuple[str, date | None]] = []