Get the repo ready for F-Droid

- License: AGPL-3.0-or-later (LICENSE, every package.json, README).
- MUSICSHARE_FOSS=1 builds leave out the only closed-source code, Google's
  ML Kit / Play Services barcode scanner bundled by expo-camera; the scan
  screen then decodes small camera snapshots with jsQR instead.
- Expo modules build from source rather than from precompiled AARs, as
  F-Droid requires (that's also what makes the scanner switch take effect).
  Verified: a FOSS build contains no ML Kit or Play Services classes.
- Release builds default to the production server, and come out unsigned
  without our upload key (F-Droid signs with its own). versionCode 1.
- Store listing in fastlane/metadata/android, a draft fdroiddata recipe in
  fdroid/, and docs/FDROID.md with the submission steps.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

docs/FDROID.md

@@ -0,0 +1,56 @@
+# Releasing on F-Droid
+
+The Android app can be built with no closed-source code: `MUSICSHARE_FOSS=1` leaves out Google's ML
+Kit / Play Services barcode scanner that expo-camera normally bundles, and the QR scanner then decodes
+camera snapshots with jsQR instead (`apps/mobile/src/lib/qrSnapshot.ts`). Everything else in the app
+is already open source. Expo's native modules are built from source rather than from Expo's
+precompiled AARs (`expo.autolinking.android.buildFromSource` in `apps/mobile/package.json`), which
+F-Droid requires and which is also what lets the scanner be switched off. Release builds without our signing key come out unsigned, which is what
+F-Droid wants: it signs with its own key.
+
+## What's in the repo for this
+
+- `LICENSE`: AGPL-3.0 (also set in every `package.json`).
+- `fastlane/metadata/android/en-US/`: the store listing F-Droid shows (title, descriptions, icon,
+  changelogs, screenshots).
+- `fdroid/tech.chrisedwards.musicshare.yml`: a draft of the build recipe for fdroiddata.
+- `apps/mobile/app.config.ts`: the `MUSICSHARE_FOSS=1` switch (turns off expo-camera's ML Kit scanner).
+
+## Before submitting
+
+1. **Publish the source somewhere public**, such as Codeberg (popular with F-Droid apps) or GitHub,
+   and put its URL in place of `PUBLIC_REPO_URL` in the recipe.
+2. **Add screenshots**: 2-8 portrait PNGs in `fastlane/metadata/android/en-US/images/phoneScreenshots/`
+   named `1.png`, `2.png`, and so on.
+3. **Tag the release**: `git tag v1.0.0 && git push --tags`. F-Droid builds from tags.
+4. **Check the FOSS build yourself**:
+   ```bash
+   cd apps/mobile
+   MUSICSHARE_FOSS=1 CI=1 npx expo prebuild --platform android --clean --no-install
+   cd android && ./gradlew :app:assembleRelease
+   # nothing from Google's closed-source libraries should be inside:
+   unzip -l app/build/outputs/apk/release/app-release*.apk | grep -iE 'mlkit|gms' || echo clean
+   ```
+
+## Submitting
+
+1. Fork https://gitlab.com/fdroid/fdroiddata, copy the recipe to `metadata/tech.chrisedwards.musicshare.yml`.
+2. Test it with `fdroid readmeta`, `fdroid lint tech.chrisedwards.musicshare` and
+   `fdroid build -v -l tech.chrisedwards.musicshare` (fdroidserver, or their Docker image).
+3. Open a merge request. Reviewers often ask for changes to how Node is installed or how npm
+   dependencies are fetched for React Native apps; that's normal.
+
+The listing will carry the **NonFreeNet** anti-feature, because the app can connect to Spotify, Apple
+Music, Last.fm and Plex. That's expected and doesn't block inclusion.
+
+## Releasing an update
+
+1. Bump `version` and `android.versionCode` in `apps/mobile/app.json`.
+2. Add `fastlane/metadata/android/en-US/changelogs/<versionCode>.txt`.
+3. Commit, tag `v<version>`, push the tag. F-Droid picks it up automatically (`AutoUpdateMode`).
+
+## IzzyOnDroid (faster alternative)
+
+IzzyOnDroid's repository lists apps from signed APKs attached to releases, usually within days, and
+F-Droid's client can add it. Attach the APK built with our key (or the FOSS build) to each release on
+the public repo and request inclusion at https://gitlab.com/IzzyOnDroid/repo.