🚀 feat: Production release preparation with GitHub Actions deployment

## Major Features
- ✅ Battery optimized auto-sync (30 min interval, ~0.4%/day)
- ✅ BuildConfig.DEBUG conditional logging (Logger.kt)
- ✅ Settings UI cleanup (SSID field removed)
- ✅ Interactive notifications (click opens app)
- ✅ Post-reboot auto-sync (BootReceiver)
- ✅ GitHub Actions deployment workflow

## Implementation Details

### Auto-Sync Architecture
- WorkManager PeriodicWorkRequest (30 min intervals)
- Gateway IP detection via network interface enumeration
- Smart sync only when on home network
- BootReceiver restarts monitoring after device reboot

### Logging System
- Logger.kt object with BuildConfig.DEBUG checks
- Debug logs only in DEBUG builds
- Error/warning logs always visible
- All components updated (NetworkMonitor, SyncWorker, WebDavSyncService, etc.)

### UI Improvements
- Removed confusing SSID field from Settings
- Gateway detection fully automatic
- Material Design 3 info boxes
- Cleaner, simpler user interface

### Notifications
- PendingIntent opens MainActivity on click
- setAutoCancel(true) for auto-dismiss
- Broadcast receiver for UI refresh on sync

### GitHub Actions
- Automated APK builds on push to main
- Signed releases with proper keystore
- 3 APK variants (universal, arm64-v8a, armeabi-v7a)
- Semantic versioning: YYYY.MM.DD + build number
- Comprehensive release notes with installation guide

## Documentation
- README.md: User-friendly German guide
- DOCS.md: Technical architecture documentation
- GITHUB_ACTIONS_SETUP.md: Deployment setup guide

## Build Configuration
- Signing support via key.properties
- APK splits for smaller downloads
- ProGuard enabled with resource shrinking
- BuildConfig generation for DEBUG flag

android/app/src/main/AndroidManifest.xml

@@ -2,16 +2,20 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
 
+    <!-- Network & Sync Permissions -->
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
     <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
-    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
-    <uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />
+    
+    <!-- Notifications -->
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    
+    <!-- Battery Optimization (for WorkManager background sync) -->
     <uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />
-    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
-    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_DATA_SYNC" />
+    
+    <!-- BOOT Permission - CRITICAL für Auto-Sync nach Neustart! -->
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
 
     <application
         android:name=".SimpleNotesApplication"
@@ -45,6 +49,17 @@
             android:name=".SettingsActivity"
             android:parentActivityName=".MainActivity" />
 
+        <!-- Boot Receiver - Startet WorkManager nach Reboot -->
+        <receiver
+            android:name=".sync.BootReceiver"
+            android:enabled="true"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.BOOT_COMPLETED" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </receiver>
+
     </application>
 
 </manifest>