Improve E2EE robustness and Android permissions

- Add IV validation and key sanitization for encryption
- Add stale key repair for media decryption failures
- Block READ_MEDIA_IMAGES/VIDEO permissions (use photo picker)
- Prevent double-tap crashes in media picker
- Clear media cache on logout
- Persist versionCode/buildNumber in app.json
- Bump Android targetSdk to 35

apps/mobile/android/app/build.gradle

@@ -93,7 +93,7 @@ android {
         applicationId 'com.sauci.app'
         minSdkVersion rootProject.ext.minSdkVersion
         targetSdkVersion rootProject.ext.targetSdkVersion
-        versionCode 1
+        versionCode 9
         versionName "1.0.0"
     }
     signingConfigs {