todo: what the calendar API deliberately cannot write

recurrence, alarms, attendees and EXDATE. all four read correctly and none can
be authored — which is what the agent skill still drops to raw DAV for. filed
with an order to do them in (EXDATE first: "cancel next Tuesday" is a thing the
owner will say and the honest answer today is a refusal) and the reason the API
stops where it does.

new theme, because burying a calendar gap under plugin-repos is where it goes to
be lost.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

todo/calendar/_index.md

@@ -0,0 +1,8 @@
+---
+theme: calendar
+heading: "Calendar and contacts"
+kind: theme
+---
+
+The caldav plugin: Radicale, the DAV door phones sync against, the `/calendar` and `/contacts` screens,
+and the JSON API both those screens and the agent skill are built on.