perf(android): R8, bitmap downscaling, edge-to-edge; recover device compat; publish to production

Device compatibility (regression fix):
- The CAMERA permission (from zxing_barcode_scanner / image_picker) implicitly
  required android.hardware.camera, excluding camera-less devices — Play showed
  Automotive -96%, Chromebook -86%, TV -25%. Declare camera & location
  uses-feature required="false" to keep those devices supported.
- Detect a real camera at runtime (PackageManager.FEATURE_CAMERA_ANY via the
  existing MethodChannel), cache it at bootstrap, and hide the QR scan button and
  the camera photo-source option when absent, so no broken actions are offered.

Play "app optimization" recommendations:
- Enable R8 (isMinifyEnabled + isShrinkResources) with keep rules for the
  OCR (tesseract4android), SQLCipher and notifications JNI/reflection code.
- Bitmap downscaling: cacheWidth/cacheHeight (and ResizeImage for avatars) on
  list thumbnails and avatars so photos decode to on-screen size, not full res.
- Edge-to-edge: opt in with transparent system bars in main().

Release flow:
- Tagged builds now publish to the production track at 100% (was internal);
  add a manual deploy_internal lane as a QA safety net.
- Document country/region availability as a Play Console setting (not in-repo).

docs/release.md

@@ -15,7 +15,11 @@ git tag v0.1.0 && git push origin v0.1.0
 ```
 
 Forgejo Actions ([`../.forgejo/workflows/release.yml`](../.forgejo/workflows/release.yml))
-builds the signed AAB/APK and uploads to Play's **internal** track. No passwords are typed.
+builds the signed AAB/APK and uploads to Play's **production** track at **100%
+rollout**. No passwords are typed. Because a tag now publishes to everyone
+(subject to Google review), run the [manual smoke test](#manual-smoke-test-before-shipping)
+**before** tagging. To stage on the internal track first, run
+`bundle exec fastlane deploy_internal` by hand.
 
 ## Versioning
 
@@ -123,6 +127,24 @@ listing (titles, descriptions, changelogs, screenshots) is read straight from
 `fastlane/metadata/android/`. Data Safety and content-rating answers:
 [`legal/internal/play-compliance.md`](legal/internal/play-compliance.md).
 
+Lanes:
+- `deploy_play` — upload the AAB to **production** at 100% (what CI runs on tag).
+- `deploy_internal` — same AAB to the **internal** test track (manual QA safety net).
+- `deploy_metadata` — push only the store listing (no binary).
+- `promote_production` — promote an internal release to production without a rebuild.
+
+### Country/region availability (Play Console, not this repo)
+
+Which countries the app is offered in is **not** in the repo and `fastlane supply`
+does not manage it — it's a Play Console setting. To add countries:
+**Play Console → (Tane) → Production → Countries / regions → Add countries/regions**
+(under "Availability"). Play asks you to pick countries when you first move a
+release to production; widen the list there for new markets.
+
+Note: the locales under `fastlane/metadata/android/<locale>` (`en-US`, `es-ES`)
+are **listing languages**, not countries — adding a locale improves the store
+page but does not by itself make the app available in a new country.
+
 ## Publish to F-Droid (official repo)
 
 F-Droid builds from source after a merge request to `fdroiddata`. The build recipe