feat: surface Simplified Chinese; complete 2.14.0 changelog

Add zh-CN to locales_config.xml so the community Simplified Chinese
translation (values-zh-rCN, already committed via Weblate, ~27%) is
selectable in the in-app language picker and Android's per-app-language
settings. Untranslated strings fall back to English.

Fill in the 2.14.0 changelog, which only documented #37: add the three
feature PRs that also landed on this branch — .ics restore + per-calendar
export (#32), Month week numbers (#25), edit-screen title wrapping (#33) —
plus a note for the new Chinese translation, the missing [#N] link refs,
and the re-synced fastlane en-US changelog.

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

app/src/main/res/xml/locales_config.xml

@@ -12,4 +12,5 @@
     <locale android:name="de" />
     <locale android:name="es" />
     <locale android:name="it" />
+    <locale android:name="zh-CN" />
 </locale-config>