feat(filter,settings): calendar filter in drawer + settings (v0.5.0)

M3 — calendar filter: the navigation drawer now hosts the calendar list
inline (grouped by account, colour swatch + checkbox per calendar). Hidden
calendars are persisted app-side and filtered centrally in the repository,
so month/week/day re-filter live the moment a checkbox flips. Drawer trimmed
to Today, the calendar filter, and Settings, with leading icons and a clear
title/section type scale; the stubbed jump-to-date entry (M2) was removed.

M4 — settings: full-screen destination with appearance (theme System/Light/
Dark, Material You dynamic colour auto-disabled < API 31, week start Auto/Mon/
Sun), language (per-app locales via AppCompat, persisted to API 29), and an
about section (version, licence, source link). Theme is driven by one
activity-scoped settings source so changes apply app-wide at once. Week start
now drives the month grid and week view; Auto follows the locale.

Also:
- default view switched from month to week
- Settings screen handles system back (was closing the app)
- fix pre-existing NonObservableLocale/LocalContextConfigurationRead lint
  errors in EventDetailScreen so CI lint is green again
- versionName/versionCode bumped to 0.5.0 / 5

Tests: repository hidden-filter (incl. live re-emit), SettingsPrefs round-trip
+ week-start resolution, filter grouping. lint + unit tests + assembleDebug green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.planning/ROADMAP.md

@@ -6,15 +6,19 @@
 |---|---|---|
 | v0.1 | Foundation & CI | complete |
 | v0.2 | Data Layer & Permission Flow | complete |
-| v0.3 | Month view | in progress |
-| v0.4 | Week view | in progress |
-| v0.5 | Day view | pending |
-| v0.6 | Event Detail Sheet | pending |
-| v0.7 | Filter & Settings | pending |
+| 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 |
+| v1.0 | Polish + jump-to-date (M2), F-Droid release | pending |
+
+Delivery ran ahead of the original table: Day view (S3) shipped in v0.3 and
+Event Detail (S4) in v0.4, so the Filter/Settings milestone became v0.5.
+Jump-to-date (M2) was deferred out of v0.5 and folds into the v1.0 polish pass.
 
 ## v1.0 — First Public Release
 
 All V1 features shipped, polished, on F-Droid. Read-only calendar.
+Remaining before v1.0: jump-to-date (M2) and a UI polish/QA pass.
 
 ## v2.0 — Write Support