Google: stop the Tasks poll erroring on a disconnected account

[KrisBraun]

Symptom

Google Tasks has no webhooks, so its sync is a durable hourly poll. When the account's OAuth grant lapses or is revoked, the channel resolves no token and the poll threw an unhandled error — once an hour, multiplied by the queue's retries, for as long as the connection stayed disconnected.

That state is expected and already surfaced: resolving no token flags the connection for re-auth, so the app shows Reconnect and only the user can clear it. It's also specific to Tasks among this connector's products — mail and calendar are push-driven, and a revoked grant simply stops delivering notifications, so nothing keeps knocking.

Fix

periodicSyncBatchFn now fetches the token through a new non-throwing tryGetTokenFn (mirroring the mail module's existing tryGetApiFn) and ends the cycle quietly when there is none:

• drops the in-flight cycle state and reports done, so the recurring schedule re-fires on its own and picks back up once the connection is restored;
• leaves last_sync_time_ untouched, so the window skipped while disconnected is re-covered by the first successful cycle rather than silently lost;
• leaves the channel enabled — this is not a teardown, unlike the deleted-task-list path, which still cancels the poll and archives links.

The initial backfill deliberately keeps using the throwing getTokenFn: the app shows a sync spinner until the backfill reports completion, so a silent early return there would leave it spinning forever.

Tests

Two cases added to src/tasks/sync.test.ts, both driven from a host whose integrations.get resolves null:

• the poll returns { done: true }, clears only the cycle state, and does not cancel the schedule, archive links, disable the channel, advance last_sync_time_, or call the API;
• the initial backfill still throws, guarding the spinner behaviour against a well-meaning future "make it quiet too".

Full connector suite: 369 passing.