feat: add NetEase as lyrics fallback after lrclib (Android + web)

Search order: lrclib exact → lrclib fuzzy search → NetEase.
NetEase has strong coverage for Asian/Japanese music that lrclib misses.
Duration-matched candidate selection on all three steps.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

android/app/src/main/kotlin/com/novasonic/app/api/LrcLibClient.kt

@@ -21,6 +21,21 @@ data class LrcLibResponse(
     val syncedLyrics: String? = null,
 )
 
+@Serializable
+private data class NetEaseSearchResp(
+    val result: NetEaseResult? = null,
+    val code: Int = 0,
+)
+@Serializable
+private data class NetEaseResult(val songs: List<NetEaseSong> = emptyList())
+@Serializable
+private data class NetEaseSong(val id: Long = 0, val duration: Long = 0)
+
+@Serializable
+private data class NetEaseLyricsResp(val lrc: NetEaseLrc? = null, val code: Int = 0)
+@Serializable
+private data class NetEaseLrc(val lyric: String? = null)
+
 data class LrcLine(val timeMs: Long, val text: String)
 
 fun parseLrc(lrc: String): List<LrcLine> {
@@ -53,7 +68,7 @@ object LrcLibClient {
         album: String?,
         durationSecs: Int?,
     ): LrcLibResponse? {
-        // 1. Exact match — fastest, most accurate when metadata is clean
+        // 1. lrclib exact match
         val exact = runCatching {
             client.get("https://lrclib.net/api/get") {
                 parameter("artist_name", artist)
@@ -64,26 +79,65 @@ object LrcLibClient {
         }.getOrNull()
         if (exact != null) return exact
 
-        // 2. Fuzzy search fallback — handles artist name mismatches (e.g. "Utada" vs "Hikaru Utada")
+        // 2. lrclib fuzzy search — handles artist name mismatches
         val candidates = runCatching {
             client.get("https://lrclib.net/api/search") {
                 parameter("track_name", title)
                 if (artist.isNotBlank()) parameter("artist_name", artist)
             }.body<List<LrcLibResponse>>()
-        }.getOrNull() ?: return null
+        }.getOrNull()
 
-        if (candidates.isEmpty()) return null
-
-        return if (durationSecs != null && durationSecs > 0) {
-            val synced = candidates.filter { !it.syncedLyrics.isNullOrBlank() }
-            val pool   = synced.ifEmpty { candidates }
-            pool.minByOrNull { kotlin.math.abs(it.duration - durationSecs) }
-                ?.takeIf { kotlin.math.abs(it.duration - durationSecs) <= 5.0 }
-                ?: synced.firstOrNull()
-                ?: candidates.firstOrNull()
-        } else {
-            candidates.firstOrNull { !it.syncedLyrics.isNullOrBlank() }
-                ?: candidates.firstOrNull()
+        val lrclibResult = candidates?.let { list ->
+            if (list.isEmpty()) return@let null
+            if (durationSecs != null && durationSecs > 0) {
+                val synced = list.filter { !it.syncedLyrics.isNullOrBlank() }
+                val pool   = synced.ifEmpty { list }
+                pool.minByOrNull { kotlin.math.abs(it.duration - durationSecs) }
+                    ?.takeIf { kotlin.math.abs(it.duration - durationSecs) <= 5.0 }
+                    ?: synced.firstOrNull()
+                    ?: list.firstOrNull()
+            } else {
+                list.firstOrNull { !it.syncedLyrics.isNullOrBlank() } ?: list.firstOrNull()
+            }
         }
+        if (lrclibResult != null) return lrclibResult
+
+        // 3. NetEase fallback — good coverage for Asian/Japanese music
+        val neLrc = runCatching { netEaseLyrics(artist, title, durationSecs) }.getOrNull()
+        if (!neLrc.isNullOrBlank()) {
+            return LrcLibResponse(syncedLyrics = neLrc)
+        }
+
+        return null
+    }
+
+    private suspend fun netEaseLyrics(artist: String, title: String, durationSecs: Int?): String? {
+        val query = "$artist $title".trim()
+        val search = client.get("https://music.163.com/api/search/get") {
+            parameter("s", query)
+            parameter("type", 1)
+            parameter("limit", 5)
+            header("Referer", "https://music.163.com")
+        }.body<NetEaseSearchResp>()
+
+        val songs = search.result?.songs ?: return null
+        val song = if (durationSecs != null && durationSecs > 0) {
+            val durMs = durationSecs * 1000L
+            songs.minByOrNull { kotlin.math.abs(it.duration - durMs) }
+                ?.takeIf { kotlin.math.abs(it.duration - durMs) <= 5000L }
+                ?: songs.firstOrNull()
+        } else {
+            songs.firstOrNull()
+        } ?: return null
+
+        val lyricsResp = client.get("https://music.163.com/api/song/lyric") {
+            parameter("id", song.id)
+            parameter("lv", 1)
+            parameter("kv", 1)
+            parameter("tv", -1)
+            header("Referer", "https://music.163.com")
+        }.body<NetEaseLyricsResp>()
+
+        return lyricsResp.lrc?.lyric?.takeIf { it.isNotBlank() }
     }
 }