release: cut 0.3.1 — fix the launch crash in minified builds

R8 kept androidx.work.impl.WorkDatabase_Impl but pruned its no-arg
constructor: nothing calls it directly, Room only reaches it reflectively.
Room then threw InstantiationException, surfacing as "Failed to create an
instance of androidx.work.impl.WorkDatabase". WorkManager builds that
database from a startup ContentProvider, so 0.3.0 died before any of our
code ran — every install, every launch.

We don't depend on WorkManager directly; it arrives via Glance. AGP 9's
stricter R8 is what tipped this over, which is why 0.3.0 was the first
release to hit it.

Keep the Room no-arg constructor, and the ListenableWorker constructor
alongside it — same pruning hazard on the path WorkManager uses to
instantiate workers by name, which would have bitten once a Glance widget
update actually ran.

Reproduced the reporter's stack trace frame-for-frame on a releaseTest
build, then confirmed it launches clean afterwards. Fixes #1.

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

CHANGELOG.md

@@ -7,6 +7,13 @@ All notable changes to this project are documented here. The format follows
 
 ## [Unreleased]
 
+## [0.3.1] - 2026-07-20
+
+### Fixed
+- Agendula no longer crashes on launch. Every 0.3.0 install was affected: the
+  release build stripped a constructor that the background-work scheduler needs
+  to open its database, and that happens before the app draws anything.
+
 ## [0.3.0] - 2026-07-19
 
 ### Added