Connector: Google Calendar (OAuth)

[fberrez]

First-class Google Calendar connector via OAuth, beyond the current public-ICS-URL approach, feeding the existing agenda widget.

Scope

• OAuth client + token storage (encrypted), refresh handling.
• Returns the same normalized agenda data shape the ics connector produces, so the agenda widget is unchanged.
• Studio: connect/disconnect flow, calendar selection.

Open question

• OAuth redirect URI is awkward on pure-local installs (no public callback). Decide: device-code flow vs a small hosted callback helper vs documented self-host redirect. Document the chosen path.