feat(settings): graduated version tracking + Jellyfin clientInfo auto-sync

Settings "App version" now shows a graduated build identifier (utils/version.ts,
read defensively so it never crashes the screen):
- dev / local            -> "0.54.1 - branch - commit"
- develop / CI / preview  -> "0.54.1 - commit"
- production (store/TestFlight) -> "0.54.1 (42)"

app.config.js injects extra.build {commit, branch, profile, builtAt} from
EAS_BUILD_* / GITHUB_* / local git; build-apps.yml passes the PR branch+commit.
JellyfinProvider now sends APP_VERSION (auto-synced from expo-application) in its
clientInfo/auth header instead of a hardcoded "0.54.1". Version scheme unchanged.

.github/workflows/build-apps.yml

@@ -11,6 +11,12 @@ on:
   push:
     branches: [develop, master]
 
+# Exposed to `expo prebuild` (app.config.js → extra.build) so Settings can show the
+# branch + commit a CI build was made from. EAS cloud builds use EAS_BUILD_* instead.
+env:
+  EXPO_PUBLIC_GIT_BRANCH: ${{ github.head_ref || github.ref_name }}
+  EXPO_PUBLIC_GIT_COMMIT: ${{ github.sha }}
+
 jobs:
   build-android-phone:
     if: (!contains(github.event.head_commit.message, '[skip ci]'))