release: cut v2.5.0 — home-screen widgets, agenda, jump-to-date, quick actions

Bundles the unreleased Tier 2/3 work into one release:

- Home-screen widgets (Glance): an "Upcoming" agenda widget and a month-grid
  widget, both reusing the in-app grouping/layout (groupAgendaDays,
  layoutMonthWeeks) via a Hilt WidgetEntryPoint, honouring hidden-calendar
  filters and refreshing on PROVIDER_CHANGED / date rollover.
- App shortcut: launcher long-press "New event", routed through the shared
  WidgetNavRequest.Create channel into the create-event form.
- Agenda view and jump-to-date (already merged via #3/#4) are documented here
  as part of the shipped version.

Bumps versionCode 20500 / versionName 2.5.0, moves the CHANGELOG Unreleased
section under [2.5.0], updates ROADMAP/STATE, and adds EN+DE strings.

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

.planning/STATE.md

@@ -8,8 +8,10 @@
 v2.1.0 (month event grid, drawer view tabs, cursor fix) shipped 2026-06-15.
 **Phase:** post-2.1 backlog work. v2.2.0 (tap-to-create in day/week + local
 calendar management) and v2.3.0 (Material 3 grouped-list redesign of Settings,
-the calendar manager and the navigation drawer) both shipped 2026-06-16. The
-backlog is now organised by theme in `ROADMAP.md`.
+the calendar manager and the navigation drawer) both shipped 2026-06-16;
+v2.4.0 (per-event colors) and v2.5.0 (jump-to-date, Agenda view, home-screen
+agenda + month widgets, and a "New event" launcher shortcut) shipped
+2026-06-17. The backlog is now organised by theme in `ROADMAP.md`.
 
 ## Progress