feat(android): companion in-app WebView footer controls + loader; shared debug key; v0.4.7

- InAppBrowser now has a bottom control bar (back/forward/reload/open-in-browser/
  close) mirroring the web mobile footer, plus a centered loading screen
  (app favicon + progress bar) instead of a bare top bar over black.
- Commit a repo-dedicated debug keystore and pin signingConfigs.debug to it so
  every machine — and the published companion download — signs debug builds with
  the SAME key (fixes "App not installed" signature-mismatch on update). Force v1+v2.
- Bump versionCode 10→11, versionName 0.4.6→0.4.7.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Android/app/build.gradle.kts

@@ -11,20 +11,40 @@ android {
         applicationId = "com.archipelago.app"
         minSdk = 26
         targetSdk = 35
-        versionCode = 10
-        versionName = "0.4.6"
+        versionCode = 11
+        versionName = "0.4.7"
 
         vectorDrawables {
             useSupportLibrary = true
         }
     }
 
+    signingConfigs {
+        // Repo-dedicated debug keystore (committed at app/debug.keystore) so every
+        // machine — and the published companion download — signs debug builds with
+        // the SAME key. Without this, Gradle falls back to each machine's
+        // ~/.android/debug.keystore, so a build from a different machine has a
+        // different signature and the phone rejects the update ("App not installed").
+        getByName("debug") {
+            storeFile = file("debug.keystore")
+            storePassword = "android"
+            keyAlias = "androiddebugkey"
+            keyPassword = "android"
+            // Force both legacy JAR (v1) and APK Signature Scheme v2. AGP drops v1
+            // for minSdk>=24, but some OEM package installers (e.g. Samsung) reject
+            // a v2-only sideload with "App not installed" — keep v1 for max compat.
+            enableV1Signing = true
+            enableV2Signing = true
+        }
+    }
+
     buildTypes {
         debug {
             // Separate app ID so a debug/test build installs alongside the
             // release app instead of colliding on signature.
             applicationIdSuffix = ".debug"
             versionNameSuffix = "-debug"
+            signingConfig = signingConfigs.getByName("debug")
         }
         release {
             isMinifyEnabled = true