feat: implement station navigation and update to SDK 37

- Implement `seekToNext` and `seekToPrevious` in `PlayerService` to allow switching between radio stations.
- Update `compileSdk` and `targetSdk` to 37 and bump version to 14.6.
- Modify `PlayerService` to remain active while paused to improve playback resumption.
- Modernize media resumption logic using Media3 `isRecent` check instead of legacy extras.
- Refactor `DefaultRenderersFactory` to use non-nullable `AudioSink` return types.
- General code cleanup using KTX extensions (e.g., `View.isEmpty()`) and Kotlin property access syntax.

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

@@ -120,7 +120,7 @@ class AddStationFragment : Fragment(),
                 if (searchEditText != null) {
                     searchEditText.requestFocus()
                     val imm = requireContext().getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
-                    imm.showSoftInput(searchEditText, InputMethodManager.SHOW_IMPLICIT)
+                    imm.showSoftInput(searchEditText, 0)
                 }
             }
         }