release: cut 0.4.0 — the first translated release

Ships the first community translations: German (98%) and Brazilian
Portuguese (100%), both from Weblate, plus the translation infrastructure
and the Codeberg forge move that had accumulated under Unreleased.

A minor bump rather than a patch: two new user-facing languages is a
feature, the way 0.3.0 was cut for Reminders.

versionCode is the derived 400 (MAJOR*10000 + MINOR*100 + PATCH), and
scripts/sync_changelog_to_fastlane.sh generated changelogs/400.txt so the
official F-Droid listing shows this version's "What's New". At 908 chars
it exceeds the script's 500-char advisory and may be truncated in-client
— consistent with past feature releases (0.2.0 ran 1811, 0.3.0 692).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0146mhMLZ5AqJSZkADDc92Jz

CHANGELOG.md

@@ -7,7 +7,14 @@ All notable changes to this project are documented here. The format follows
 
 ## [Unreleased]
 
+## [0.4.0] - 2026-08-31
+
 ### Added
+- Agendula now speaks **German** and **Brazilian Portuguese**, the first
+  community translations. Pick one under **Settings → App language**, or in
+  Android's own per-app language settings; leave it on *System default* and
+  Agendula follows your phone. Anything not yet translated falls back to
+  English.
 - Agendula can now be translated. Pick or request a language on Weblate and
   translate in the browser — the link sits at the top of the language picker in
   **Settings → App language**. Partial translations are fine; anything