feat: add custom house launcher icon, themed splash screen, and F-Droid metadata

Replace default Flutter icon with white house on sage green (#7A9A6D) background.
Add native splash screen with themed colors (#F5F0E8 light, #2A2520 dark).
Include F-Droid metadata with screenshots for de-DE and en-US locales.
Add CHANGELOG.md tracking all releases from v1.0.0 to v1.1.3.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pubspec.yaml

@@ -31,6 +31,31 @@ dev_dependencies:
   riverpod_generator: ^4.0.3
   drift_dev: ^2.31.0
   build_runner: ^2.4.0
+  flutter_launcher_icons: ^0.14.3
+  flutter_native_splash: ^2.4.5
+
+flutter_launcher_icons:
+  android: true
+  ios: false
+  image_path: "assets/icon/ic_launcher.png"
+  adaptive_icon_background: "#7A9A6D"
+  adaptive_icon_foreground: "assets/icon/ic_launcher_foreground.png"
+  min_sdk_android: 21
+
+flutter_native_splash:
+  color: "#F5F0E8"
+  color_dark: "#2A2520"
+  image: "assets/icon/ic_launcher.png"
+  image_dark: "assets/icon/ic_launcher.png"
+  android: true
+  ios: false
+  android_12:
+    color: "#F5F0E8"
+    color_dark: "#2A2520"
+    image: "assets/icon/ic_launcher_foreground.png"
+    image_dark: "assets/icon/ic_launcher_foreground.png"
+    icon_background_color: "#7A9A6D"
+    icon_background_color_dark: "#7A9A6D"
 
 flutter:
   uses-material-design: true