refactor(branding): rename project to LockScreenWallpaper across repo

Standardize branding by renaming Wechselbild to LockScreenWallpaper.
This updates UI strings, configs, and plugin metadata for consistency.

- Rename branding across UI, docs, and config in the repo
- Update Android UI strings and notification titles to LockScreenWallpaper

src-tauri/Cargo.lock

@@ -1662,6 +1662,17 @@ dependencies = [
  "scopeguard",
 ]
 
+[[package]]
+name = "lockscreenwallpaper"
+version = "0.1.0"
+dependencies = [
+ "serde",
+ "serde_json",
+ "tauri",
+ "tauri-build",
+ "tauri-plugin-wallpaper",
+]
+
 [[package]]
 name = "log"
 version = "0.4.33"
@@ -3864,17 +3875,6 @@ dependencies = [
  "windows-core 0.61.2",
 ]
 
-[[package]]
-name = "wechselbild"
-version = "0.1.0"
-dependencies = [
- "serde",
- "serde_json",
- "tauri",
- "tauri-build",
- "tauri-plugin-wallpaper",
-]
-
 [[package]]
 name = "winapi"
 version = "0.3.9"