Add support for Android TV and update dependencies

*   Implement initial Android TV support, including `LEANBACK_LAUNCHER` intent filter, hardware feature declarations, and television-specific layouts for the player, search results, and dialogs.
*   Add a splash/loading screen for the TV interface and a dedicated `SplashTheme`.
*   Improve DPAD navigation by adding `OnKeyListener` for station cards and allowing focus on internal elements.
*   Update `LayoutHolder` and `PlayerFragment` to handle TV layouts and add previous/next station navigation buttons.
*   Adjust `PreferencesHelper` to disable station editing by default on TV devices.
*   Update `androidx.media3` to v1.10.0, `work-runtime-ktx` to v2.11.2, and add `androidx.leanback` dependency.
*   Bump `versionCode` to 144 and `versionName` to 14.4.
*   Refactor `PlayerService` to simplify sleep timer cancellation logic.
*   Remove stale copyright headers and license comments from several Kotlin files.

app/src/main/java/com/michatec/radio/PlayerService.kt

@@ -210,12 +210,9 @@ class PlayerService : MediaLibraryService() {
     /* Cancels sleep timer */
     private fun cancelSleepTimer() {
         if (this::sleepTimer.isInitialized) {
-            if (manuallyCancelledSleepTimer) {
-                sleepTimerTimeRemaining = 0L
-                sleepTimer.cancel()
-            }
-            manuallyCancelledSleepTimer = false
+            sleepTimer.cancel()
         }
+        sleepTimerTimeRemaining = 0L
         // store timer state
         PreferencesHelper.saveSleepTimerRunning(isRunning = false)
     }