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>

app/src/main/res/values/strings.xml

@@ -27,8 +27,6 @@
     <string name="month_today_action">Today</string>
     <string name="month_more_actions">More actions</string>
     <string name="month_open_menu">Open menu</string>
-    <string name="month_action_filter">Calendars</string>
-    <string name="month_action_jump_to_date">Jump to date…</string>
     <string name="month_action_settings">Settings</string>
     <string name="month_a11y_today_prefix">Today</string>
 
@@ -76,4 +74,34 @@
     <string name="view_month">Month</string>
     <string name="view_week">Week</string>
     <string name="view_day">Day</string>
+
+    <!-- Calendar filter (M3) -->
+    <string name="filter_title">Calendars</string>
+
+    <!-- Settings (M4) -->
+    <string name="settings_title">Settings</string>
+    <string name="settings_back">Back</string>
+    <string name="settings_section_appearance">Appearance</string>
+    <string name="settings_theme">Theme</string>
+    <string name="settings_theme_system">System</string>
+    <string name="settings_theme_light">Light</string>
+    <string name="settings_theme_dark">Dark</string>
+    <string name="settings_dynamic_color">Dynamic colour</string>
+    <string name="settings_dynamic_color_unavailable">Requires Android 12 or newer</string>
+    <string name="settings_week_start">Week starts on</string>
+    <string name="settings_week_start_auto">Automatic</string>
+    <string name="settings_week_start_monday">Monday</string>
+    <string name="settings_week_start_sunday">Sunday</string>
+    <string name="settings_section_language">Language</string>
+    <string name="settings_language">App language</string>
+    <string name="settings_language_auto">System default</string>
+    <string name="settings_language_german">Deutsch</string>
+    <string name="settings_language_english">English</string>
+    <string name="settings_section_about">About</string>
+    <string name="settings_version">Version</string>
+    <string name="settings_license">License</string>
+    <string name="settings_license_value">MIT</string>
+    <string name="settings_source">Source code</string>
+    <string name="settings_source_open">Open</string>
+    <string name="about_source_url" translatable="false">https://gitea.jeanlucmakiola.de/makiolaj/calendula</string>
 </resources>