fix: prefer local file for cover/lyrics save and update build dependencies

- Cover art: extract from downloaded file first, fall back to URL download
- Lyrics: check embedded lyrics/sidecar LRC before fetching online
- Add audioFilePath param to FetchAndSaveLyrics (Go, Kotlin, Swift, Dart)
- Handle SAF content:// URIs for lyrics extraction in Kotlin bridge
- Update Go 1.25.7 -> 1.25.8, Gradle 9.3.1 -> 9.4.1, Kotlin 2.2.21 -> 2.3.20
- Update NDK r27d -> r28b, Flutter FVM 3.41.4 -> 3.41.5
- Upgrade all Flutter and Go module dependencies to latest

android/app/src/main/kotlin/com/zarz/spotiflac/MainActivity.kt

@@ -2516,12 +2516,27 @@ class MainActivity: FlutterFragmentActivity() {
                             val spotifyId = call.argument<String>("spotify_id") ?: ""
                             val durationMs = call.argument<Number>("duration_ms")?.toLong() ?: 0L
                             val outputPath = call.argument<String>("output_path") ?: ""
+                            val rawAudioFilePath = call.argument<String>("audio_file_path") ?: ""
                             val response = withContext(Dispatchers.IO) {
+                                var safAudioTemp: String? = null
                                 try {
-                                    Gobackend.fetchAndSaveLyrics(trackName, artistName, spotifyId, durationMs, outputPath)
+                                    // Resolve SAF content:// URI to a temp file the Go backend can read
+                                    val audioFilePath = if (rawAudioFilePath.startsWith("content://")) {
+                                        val uri = Uri.parse(rawAudioFilePath)
+                                        val tempPath = copyUriToTemp(uri)
+                                        safAudioTemp = tempPath
+                                        tempPath ?: ""
+                                    } else {
+                                        rawAudioFilePath
+                                    }
+                                    Gobackend.fetchAndSaveLyrics(trackName, artistName, spotifyId, durationMs, outputPath, audioFilePath)
                                     """{"success":true}"""
                                 } catch (e: Exception) {
                                     """{"success":false,"error":"${e.message?.replace("\"", "'")}"}"""
+                                } finally {
+                                    if (safAudioTemp != null) {
+                                        try { File(safAudioTemp).delete() } catch (_: Exception) {}
+                                    }
                                 }
                             }
                             result.success(response)