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/lib/ui/photo_pick.dart

@@ -4,6 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:image_picker/image_picker.dart';
 
 import '../i18n/strings.g.dart';
+import '../services/camera_availability.dart';
 
 /// Asks the user to take a photo or pick one from the gallery, then returns its
 /// bytes (or null if cancelled/unavailable). Camera failures — e.g. on desktop,
@@ -16,12 +17,15 @@ Future<Uint8List?> pickPhoto(BuildContext context) async {
       child: Column(
         mainAxisSize: MainAxisSize.min,
         children: [
-          ListTile(
-            key: const Key('photo.source.camera'),
-            leading: const Icon(Icons.photo_camera_outlined),
-            title: Text(t.photo.camera),
-            onTap: () => Navigator.of(sheetContext).pop(ImageSource.camera),
-          ),
+          // Only offer the camera when the device actually has one; camera-less
+          // devices (Chromebooks, Automotive, some TVs) fall back to gallery.
+          if (deviceHasCamera)
+            ListTile(
+              key: const Key('photo.source.camera'),
+              leading: const Icon(Icons.photo_camera_outlined),
+              title: Text(t.photo.camera),
+              onTap: () => Navigator.of(sheetContext).pop(ImageSource.camera),
+            ),
           ListTile(
             key: const Key('photo.source.gallery'),
             leading: const Icon(Icons.photo_library_outlined),
@@ -57,12 +61,15 @@ Future<List<Uint8List>> pickPhotos(BuildContext context) async {
       child: Column(
         mainAxisSize: MainAxisSize.min,
         children: [
-          ListTile(
-            key: const Key('photos.source.camera'),
-            leading: const Icon(Icons.photo_camera_outlined),
-            title: Text(t.photo.camera),
-            onTap: () => Navigator.of(sheetContext).pop(ImageSource.camera),
-          ),
+          // Only offer the camera when the device actually has one; camera-less
+          // devices (Chromebooks, Automotive, some TVs) fall back to gallery.
+          if (deviceHasCamera)
+            ListTile(
+              key: const Key('photos.source.camera'),
+              leading: const Icon(Icons.photo_camera_outlined),
+              title: Text(t.photo.camera),
+              onTap: () => Navigator.of(sheetContext).pop(ImageSource.camera),
+            ),
           ListTile(
             key: const Key('photos.source.gallery'),
             leading: const Icon(Icons.photo_library_outlined),