Add Capacitor Android packaging (APK) for Cafe Bazaar / Myket

- Next static export (output: export) wrapped by Capacitor; appId
  com.bargevasat.app, appName «برگ وسط»
- android/ native project + @capacitor/app; hardware back handled by
  CapacitorBack (back a screen, exit at home)
- npm scripts (cap:sync, android:open, android:apk), ANDROID.md
- Gradle Maven-mirror init-script template (dl.google.com/Maven Central are
  blocked in Iran — same reason NuGet is mirrored)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package.json

@@ -6,9 +6,14 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint"
+    "lint": "eslint",
+    "cap:sync": "next build && npx cap sync android",
+    "android:open": "npx cap open android",
+    "android:apk": "npm run cap:sync && cd android && gradlew.bat assembleDebug"
   },
   "dependencies": {
+    "@capacitor/app": "^8.1.0",
+    "@capacitor/core": "^8.4.0",
     "@microsoft/signalr": "^10.0.0",
     "clsx": "^2.1.1",
     "framer-motion": "^12.40.0",
@@ -20,6 +25,8 @@
     "zustand": "^5.0.14"
   },
   "devDependencies": {
+    "@capacitor/android": "^8.4.0",
+    "@capacitor/cli": "^8.4.0",
     "@tailwindcss/postcss": "^4",
     "@types/node": "^20",
     "@types/react": "^19",