release: cut v1.4.0 — reminder notifications

Version bumped to 1.4.0 / 12. No code changes beyond the version — 1.4.0 is
the reviewed-and-approved reminder slice: the EVENT_REMINDER receiver posting
due CalendarAlerts on a dedicated channel, tap-to-detail, the one-time
onboarding step requesting POST_NOTIFICATIONS with the duplicate-reminders
warning, and the Settings mirror. CHANGELOG [1.4.0] carries the details.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.4.0] — 2026-06-11
+
 ### Added
 - Reminder notifications (v1.4): Calendula now delivers event reminders as
   notifications itself — the system schedules them but posts nothing, so a
@@ -22,6 +24,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   reminders toggle (default on) with the duplicate-reminders hint; turning it
   on re-requests the notification permission when missing
 
+### Fixed
+- `versionName`/`versionCode` bumped to 1.4.0 / 12
+
 ## [1.3.0] — 2026-06-11
 
 ### Added