feat: Default-Wallpaper-Fallback und neues Wallpaper

Greeter fällt auf mitgeliefertes Package-Wallpaper zurück, wenn kein
Background konfiguriert ist. Wallpaper ersetzt durch Daniel Leone's
"Snowy Mountain" (Unsplash License).

CLAUDE.md

@@ -41,5 +41,6 @@ uv run moongreet
 - `users.py` — Benutzer aus /etc/passwd, Avatare, GTK-Themes
 - `sessions.py` — Wayland/X11 Sessions aus .desktop Files
 - `power.py` — Reboot/Shutdown via loginctl
-- `greeter.py` — GTK4 UI (Overlay-Layout)
+- `i18n.py` — Locale-Erkennung (LANG / /etc/locale.conf) und String-Tabellen (DE/EN)
+- `greeter.py` — GTK4 UI (Overlay-Layout), Faillock-Warnung nach 2 Fehlversuchen
 - `main.py` — Entry Point, GTK App, Layer Shell Setup

data/CREDITS.md

@@ -2,7 +2,7 @@
 
 ## wallpaper.jpg
 
-- **Title**: Canyon Mountains on Night Sky
-- **Author**: eberhard grossgasteiger
-- **Source**: https://www.pexels.com/photo/canion-mountains-on-night-sky-2098428/
-- **License**: Pexels License (free for personal and commercial use)
+- **Title**: Snowy Mountain
+- **Author**: Daniel Leone
+- **Source**: https://unsplash.com/de/fotos/snowy-mountain-g30P1zcOzXo
+- **License**: Unsplash License (free for personal and commercial use, attribution not required)

src/moongreet/greeter.py

@@ -25,6 +25,7 @@ LAST_USER_PATH = Path("/var/cache/moongreet/last-user")
 FAILLOCK_MAX_ATTEMPTS = 3
 PACKAGE_DATA = files("moongreet") / "data"
 DEFAULT_AVATAR_PATH = PACKAGE_DATA / "default-avatar.svg"
+DEFAULT_WALLPAPER_PATH = PACKAGE_DATA / "wallpaper.jpg"
 AVATAR_SIZE = 128
 
 
@@ -69,9 +70,12 @@ class GreeterWindow(Gtk.ApplicationWindow):
         self.set_child(overlay)
 
         # Background wallpaper (blurred and darkened)
-        if self._config.background and self._config.background.exists():
+        bg_path = self._config.background
+        if not bg_path or not bg_path.exists():
+            bg_path = Path(str(DEFAULT_WALLPAPER_PATH))
+        if bg_path.exists():
             background = Gtk.Picture()
-            background.set_filename(str(self._config.background))
+            background.set_filename(str(bg_path))
             background.set_content_fit(Gtk.ContentFit.COVER)
             background.set_hexpand(True)
             background.set_vexpand(True)