Add @aris/source-caldav package that fetches calendar events from any
CalDAV server via tsdav + ical.js.
- Supports Basic auth and OAuth via explicit authMethod discriminant
- serverUrl provided at construction time, not hardcoded
- Optional timeZone for correct local day boundaries
- Credentials cleared from memory after client login
- Failed calendar fetches logged, not silently dropped
- Login promise cached with retry on failure
Co-authored-by: Ona <no-reply@ona.com>
