Add vicinae-todo extension

[UpayanChatterjee]

New extension: Todo List (vicinae-todo)

A todo-list extension with natural-language quick add and optional two-way Google Tasks sync.

Commands

• Manage Todos (view) — tasks grouped into Overdue / Today / Upcoming / No Date / Completed sections, with subtasks, snooze actions (tomorrow / next week), inline edit form, and search.
• Add Todo (no-view, one text argument) — natural-language quick add: buy milk tomorrow, pay rent on jun 20, finish slides by monday. Date phrases are parsed with chrono-node and stripped from the title.

Google Tasks sync (optional)

• Fully opt-in: the extension is local-first (LocalStorage) and works without any setup.
• Users bring their own Google Cloud OAuth Desktop app credential (step-by-step setup in the README); credentials are entered via an in-app form and stored in extension LocalStorage.
• Auth is the standard OAuth 2.0 PKCE flow for desktop apps with a temporary loopback redirect server on 127.0.0.1. Network access is limited to accounts.google.com, oauth2.googleapis.com and tasks.googleapis.com — no third-party services, no binary downloads.
• Sync is two-way (last write wins), against a dedicated task list, with tombstone-based deletion propagation and native subtask mapping.

Checks

• npx vici lint passes, tsc --noEmit clean, builds with npx vici build
• npm ci verified against the committed package-lock.json
• Sync engine covered by an integration test against an in-memory fake of the Google Tasks REST API (push/pull/deletes/subtasks/idempotency)
• Errors surface as toasts (sync failures, missing configuration, OAuth timeouts)