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).

apps/app_seeds/android/app/src/main/AndroidManifest.xml

@@ -5,6 +5,19 @@
     <!-- Foreground local notifications for incoming private messages (Android 13+
          asks the user at runtime). -->
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    <!-- The CAMERA permission (pulled in by zxing_barcode_scanner for QR scanning
+         and used by image_picker) makes Android implicitly require the camera
+         hardware features, which would exclude camera-less devices — Chromebooks,
+         Android Automotive, many TVs — from Play. The app degrades gracefully
+         without a camera (gallery import still works; the scan button hides), so
+         declare these optional to keep those devices supported. Same for the
+         location features implied by ACCESS_COARSE_LOCATION. -->
+    <uses-feature android:name="android.hardware.camera" android:required="false" />
+    <uses-feature android:name="android.hardware.camera.any" android:required="false" />
+    <uses-feature android:name="android.hardware.camera.autofocus" android:required="false" />
+    <uses-feature android:name="android.hardware.location" android:required="false" />
+    <uses-feature android:name="android.hardware.location.network" android:required="false" />
+    <uses-feature android:name="android.hardware.location.gps" android:required="false" />
     <application
         android:label="Tane"
         android:name="${applicationName}"