feat(detail): full event read — surface every readable field (v0.6.0)

Round out the read-only model so the detail view shows everything
CalendarContract actually stores, ahead of write support.

Data layer:
- New domain types: Reminder, EventStatus, Availability, AccessLevel,
  AttendeeRelationship, AttendeeType; EventDetail gains reminders, status,
  availability, accessLevel, eventTimezone, selfStatus and Attendee gains
  relationship + type (all defaulted so existing callers compile)
- EventDetailProjection reads STATUS / AVAILABILITY / ACCESS_LEVEL /
  EVENT_TIMEZONE / SELF_ATTENDEE_STATUS; AttendeeProjection reads
  RELATIONSHIP + TYPE; new ReminderProjection queries CalendarContract.Reminders
- Mappers translate each provider integer code, guarding STATUS's null-vs-0
  ambiguity (0 == TENTATIVE) so an absent status reads as Confirmed
- Mapper unit tests cover every new column's codes

Detail UI:
- Status / availability / access chips under the title; cancelled also strikes
  the title through
- Reminders card with humanised lead times (plurals, DE + EN)
- Foreign-timezone card, shown only for timed events in a non-device zone
- Attendee role badges + the user's own "Your response: …" line
- http(s) URLs in the description are now tappable

URL field cut: CalendarContract exposes no Events.URL column (only the
CUSTOM_APP_URI app deep-link), so URLs are surfaced by linkifying the
description instead. Recorded in ROADMAP/CHANGELOG.

Version bumped to 0.6.0 / 6.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.planning/ROADMAP.md

@@ -9,7 +9,7 @@
 | v0.3 | Month + Week + Day views, view switcher | complete |
 | v0.4 | Event Detail (S4) + humanized recurrence | complete |
 | v0.5 | Calendar filter (M3) + Settings (M4) | complete |
-| v0.6 | Full event read — surface every readable field | pending |
+| v0.6 | Full event read — surface every readable field | complete |
 | v1.0 | Polish pass, F-Droid release | pending |
 
 Delivery ran ahead of the original table: Day view (S3) shipped in v0.3 and
@@ -30,9 +30,13 @@ columns we don't yet read/display:
 - **Attendee extras** — role (required / optional / organizer) + the user's own
   `SELF_ATTENDEE_STATUS`
 - **Timezone** (`EVENT_TIMEZONE`) — shown only when it differs from the device zone
-- **URL** — tappable link card
+- **URL** — ~~tappable link card~~ **cut**: `CalendarContract` exposes no
+  `Events.URL` column (only `CUSTOM_APP_URI`, an originating-app deep-link).
+  URLs are instead surfaced by linkifying the description text
 - **Access level / class** (private / confidential) — small chip (optional, trivial)
 
+All of the above shipped in v0.6.0 (2026-06-11).
+
 Deliberately out of v0.6:
 - Recurrence exception / modified-occurrence badges — `Instances` already
   resolves correct per-occurrence times for display; this only matters for