release: cut v2.3.0 — Material 3 grouped-list redesign of Settings, calendars & drawer

One shared Material 3 grouped-list blueprint, modelled on the ReFra gallery app
and extracted to ui/common/GroupedList.kt: CollapsingScaffold (a LargeTopAppBar
whose large title collapses into the bar on scroll) and GroupedRow
(Position-based corner grouping so a run of rows reads as one rounded card, with
press-animated corners and selected/minHeight knobs).

Settings: restructured into a category hub (About card on top, version mark at
the foot) with sliding sub-pages for Appearance, the new-event form and
Notifications. Theme, week-start and language pickers migrated from DropdownMenu
to OptionCard dialogs; token-based icon chips. New ic_gitea.xml (Simple Icons,
verbatim path) for the About "Source" button; en+de strings.

Calendar manager: same collapsing scaffold + grouped rows; shared
CalendarColorChip (neutral chip with a pastelised calendar glyph) replaces the
bright colour swatch.

Navigation drawer: branded header, grouped View switcher (active view
highlighted via secondaryContainer), filter list restyled to grouped rows with a
trailing checkbox; the whole drawer now scrolls as one.

Cards use surfaceContainerHigh for readable contrast against surface. Version
bumped to 2.3.0 / 20300. UI-only; unit tests green.

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

CHANGELOG.md

@@ -7,6 +7,24 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.3.0] — 2026-06-16
+
+### Changed
+- Redesigned Settings around the Material 3 grouped-list pattern: a large
+  title that collapses into the toolbar as you scroll, category cards on the
+  main screen, and dedicated sub-pages for Appearance, the new-event form, and
+  Notifications. The theme, week-start and language pickers now use the app's
+  standard option-card dialogs instead of dropdown menus
+- About moved to the top of Settings as a card — app icon, author, and quick
+  links to the source code and licence — with the version shown plainly at the
+  foot of the list
+- The Calendars screen now uses the same grouped-card layout and collapsing
+  title, and each calendar shows a soft pastel-tinted calendar glyph rather
+  than a plain colour swatch
+- Redesigned the navigation drawer to match: a branded header, the
+  Month / Week / Day switch and your calendars as grouped cards (with the
+  active view highlighted), and the whole drawer now scrolls as one
+
 ## [2.2.0] — 2026-06-16
 
 ### Added