Fastlane metadata format for F-Droid releases (#2501)

* add f-droid metadata support

* share version code calculation with website

* preserve blockquoted sections in changelogs

* refactor(android): simplify stable F-Droid metadata

Generate store changelogs only for stable releases and keep native version-code ownership in the existing release module.

* test(android): run F-Droid changelog suite in CI

---------

Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>

docs/android.md

@@ -15,7 +15,9 @@ EAS profiles: `development`, `production`, and `production-apk` in `packages/app
 
 ## Version codes
 
-`packages/app/app.config.js` derives Android `versionCode` from the package version with:
+`packages/app/native-release-version.js` is the single definition of native and F-Droid version-code math. Do not re-derive these numbers anywhere else — a drifted copy produces changelog files that match no published APK, and nothing fails loudly.
+
+The base version code comes from the package version:
 
 ```text
 major * 1_000_000 + minor * 1_000 + patch
@@ -145,6 +147,37 @@ Keep the excluded npm packages installed. Normal builds use them, while the F-Dr
 
 The EAS `production-apk` profile uses the large Android resource class. Release builds compile the native ABIs and run Hermes bundling in the same Gradle invocation; the default worker can exhaust its remaining memory and kill Hermes with exit code 137 even when Gradle's own heap is correctly sized.
 
+### F-Droid store metadata
+
+F-Droid reads the store listing from `fastlane/metadata/android/<locale>/` **at the repo root**. This location provides the best compatibility with the F-Droid release process.
+
+```text
+fastlane/metadata/android/
+├── en-US/                      (F-Droid fallback locale, mandatory)
+│   ├── title.txt               (<=50 chars)
+│   ├── short_description.txt   (<=80 chars)
+│   ├── full_description.txt    (<=4000 chars, limited HTML)
+│   ├── images/
+│   │   ├── icon.png            (512x512)
+│   │   ├── featureGraphic.png  (1024x500)
+│   │   └── phoneScreenshots/   (1.png, 2.png, ...)
+│   └── changelogs/             (generated — see below)
+├── ja/
+└── zh-CN/
+```
+
+Locale directories generally match `packages/app/src/i18n/locales.ts`, but note that `en` becomes `en-US`.
+
+F-Droid changelogs are generated from `CHANGELOG.md`. Run `npm run fdroid:changelogs`; `npm run fdroid:changelogs:check` verifies without writing. It is wired into the npm `version` lifecycle, so a release picks it up automatically and `git add -A` stages the result.
+
+One changelog must be generated per-ABI-split, so each version will create **four** identical version-coded entries. F-Droid caps changelogs at 500 characters, so the generator strips some content and adds a link to the full notes.
+
+Stable sync fails loudly if `CHANGELOG.md` has no entry for the version being cut. That is intentional — the release checklist requires the entry to be committed first, so an abort here means the checklist was skipped.
+
+Because the generator runs off the version in `package.json`, it must run **before** the tag is created: fdroidserver only reads metadata from the tag it builds, so the file for version N has to exist in the commit N points at.
+
+Beta releases are an explicit no-op: they do not create or rewrite F-Droid changelog files. Stable releases and promotions generate the four ABI entries from their final changelog.
+
 ### React version lockstep
 
 Keep `react` and `react-dom` pinned to the React version embedded by the current `react-native` release. React Native `0.81.x` embeds `react-native-renderer` `19.1.0`, so `packages/app` must use React `19.1.0`. Bumping React to a newer patch can build successfully but crash at JS startup on Android with `Incompatible React versions`, leaving the app on the native splash screen.