🚀 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/res/drawable/info_background.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android">
+    <solid android:color="#E3F2FD" />
+    <corners android:radius="8dp" />
+    <stroke 
+        android:width="1dp"
+        android:color="#2196F3" />
+</shape>

android/app/src/main/res/layout/activity_settings.xml

@@ -90,38 +90,44 @@
                 android:layout_marginTop="16dp"
                 android:layout_marginBottom="16dp" />
 
+            <!-- Server Status -->
             <LinearLayout
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
+                android:layout_marginBottom="8dp"
                 android:orientation="horizontal"
-                android:layout_marginBottom="8dp">
-
-                <com.google.android.material.textfield.TextInputLayout
+                android:gravity="center_vertical">
+                
+                <TextView
                     android:layout_width="0dp"
                     android:layout_height="wrap_content"
                     android:layout_weight="1"
-                    android:hint="@string/home_ssid"
-                    android:layout_marginEnd="8dp"
-                    style="@style/Widget.Material3.TextInputLayout.OutlinedBox">
-
-                    <com.google.android.material.textfield.TextInputEditText
-                        android:id="@+id/editTextHomeSSID"
-                        android:layout_width="match_parent"
-                        android:layout_height="wrap_content"
-                        android:inputType="text" />
-
-                </com.google.android.material.textfield.TextInputLayout>
-
-                <Button
-                    android:id="@+id/buttonDetectSSID"
+                    android:text="Server-Status:"
+                    android:textStyle="bold"
+                    android:textSize="14sp" />
+                    
+                <TextView
+                    android:id="@+id/textViewServerStatus"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
-                    android:layout_gravity="center_vertical"
-                    android:text="Detect"
-                    style="@style/Widget.Material3.Button.OutlinedButton" />
-
+                    android:text="Prüfe..."
+                    android:textSize="14sp"
+                    android:textColor="@android:color/darker_gray" />
+                    
             </LinearLayout>
 
+            <!-- Info Box -->
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginBottom="16dp"
+                android:padding="12dp"
+                android:background="@drawable/info_background"
+                android:text="ℹ️ Auto-Sync:\n\n• Prüft alle 30 Min ob Server erreichbar\n• Funktioniert nur im selben Netzwerk\n• Läuft auch im Hintergrund\n• Minimaler Akkuverbrauch (~0.4%/Tag)"
+                android:textSize="14sp"
+                android:lineSpacingMultiplier="1.2"
+                android:textColor="@android:color/black" />
+
             <LinearLayout
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"