chore(flutter): drop success-path diagnostic prints

Cleanup pass on the noisy debugPrints we added during the recent
debugging sessions. Remaining prints are error-path only:
- AlbumCoverCache fetch failed
- album/playlist cold-cache fetch failed
- audio_handler playbackEventStream error
- audio_handler queue supersession (rare race)
- audio_handler forward/backward fill failed
- artist_detail play failed
- cacheFirst fetchAndPopulate failed (only when tag is set)

Removed per-event chatter:
- audio_handler player-state and processingState subscribers
- audio_handler timing measurements (built initial / setAudioSources
  / forward fill / backward fill)
- audio_handler cache hit/miss per-track (fired N times per play)
- audio_handler register stream cache (verifiable via Settings)
- audio_handler.configure log
- albumProvider step-by-step lines (drift miss / online / drift hit /
  album hit but no tracks)
- playlistDetailProvider step-by-step lines (calling get / drift
  write done / 404 evicted / drift hit / playlist hit but no tracks)
- playlistsListProvider wire returned + drift rows lines
- playTracks stage timings (serverUrl / token / configure / setQueue
  / play returned)
- metadataPrefetcher warming N artists
- artist_detail play tapped — N tracks success log
- cacheFirst step-by-step (drift hit / drift miss / online / done)

`tag` parameter on cacheFirst preserved for ad-hoc instrumentation.

flutter_client/lib/cache/cache_first.dart

@@ -19,6 +19,10 @@ import 'dart:async';
 
 import 'package:flutter/foundation.dart' show debugPrint;
 
+// `tag` parameter is preserved for future ad-hoc instrumentation.
+// Normal operation only logs failure paths so the per-screen log
+// noise stays low.
+
 /// Wraps the watch + cold-cache fallback pattern. Generic over:
 ///   D — the drift row type (or TypedResult for joins)
 ///   T — the result type the caller wants (e.g. `List<ArtistRef>`)
@@ -43,13 +47,9 @@ Stream<T> cacheFirst<D, T>({
   // refresh for this stream subscription, so we don't fire one on every
   // drift re-emission (otherwise the populate cycles forever).
   var revalidated = false;
-  void log(String msg) {
-    if (tag != null) debugPrint('cacheFirst[$tag]: $msg');
-  }
 
   await for (final rows in driftStream) {
     if (rows.isNotEmpty) {
-      log('drift hit (${rows.length} rows)');
       yield toResult(rows);
       // Stale-while-revalidate: yield cache immediately, then kick off
       // a REST refresh in the background. Drift watch() picks up the
@@ -62,20 +62,18 @@ Stream<T> cacheFirst<D, T>({
       }
       continue;
     }
-    log('drift miss; checking connectivity');
     if (await isOnline()) {
-      log('online; calling fetchAndPopulate');
       try {
         await fetchAndPopulate();
-        log('fetchAndPopulate done; awaiting drift re-emit');
         // The drift watch() stream re-emits with the populated rows on
         // the next loop iteration. Don't yield here.
       } catch (e, st) {
-        log('fetchAndPopulate failed: $e\n$st');
+        if (tag != null) {
+          debugPrint('cacheFirst[$tag]: fetchAndPopulate failed: $e\n$st');
+        }
         yield toResult(rows); // empty result; caller surfaces error
       }
     } else {
-      log('offline; yielding empty');
       yield toResult(rows); // empty result; offline
     }
   }

flutter_client/lib/cache/metadata_prefetcher.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/foundation.dart' show debugPrint;
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../library/library_providers.dart';
@@ -38,7 +37,6 @@ class MetadataPrefetcher {
       if (n++ >= _topN) break;
       _swallow(_ref.read(artistProvider(id).future));
     }
-    if (n > 0) debugPrint('metadataPrefetcher: warming $n artists');
   }
 
   void _warmHome(HomeData h) {

flutter_client/lib/library/artist_detail_screen.dart

@@ -95,8 +95,6 @@ class ArtistDetailScreen extends ConsumerWidget {
                     try {
                       final tracks =
                           await ref.read(artistTracksProvider(id).future);
-                      debugPrint(
-                          'artist_detail: play tapped — ${tracks.length} tracks for $id');
                       if (tracks.isEmpty) {
                         if (context.mounted) {
                           ScaffoldMessenger.of(context).showSnackBar(

flutter_client/lib/library/library_providers.dart

@@ -187,11 +187,9 @@ final albumProvider = StreamProvider.family<
   Future<bool> fetchAndPopulate() async {
     try {
       final api = await ref.read(libraryApiProvider.future);
-      debugPrint('albumProvider($albumId): calling getAlbum');
       final fresh = await api
           .getAlbum(albumId)
           .timeout(const Duration(seconds: 10));
-      debugPrint('albumProvider($albumId): got ${fresh.tracks.length} tracks, writing to drift');
       // Collect every artist mentioned by the album + its tracks so
       // the JOINs that drive both the album header and the track rows
       // have something to bind to. Without this, drift returns null
@@ -224,7 +222,6 @@ final albumProvider = StreamProvider.family<
         b.insertAllOnConflictUpdate(db.cachedTracks,
             fresh.tracks.map((t) => t.toDrift()).toList());
       });
-      debugPrint('albumProvider($albumId): drift write done; awaiting watch re-emit');
       return true;
     } catch (e, st) {
       debugPrint('albumProvider($albumId): cold-cache fetch failed: $e\n$st');
@@ -235,7 +232,6 @@ final albumProvider = StreamProvider.family<
   await for (final albumRows in albumQuery.watch()) {
     // Case 1: no album row at all → cold-fetch.
     if (albumRows.isEmpty) {
-      debugPrint('albumProvider($albumId): drift miss, attempting cold-cache fetch');
       if (fetchAttempted) {
         // Already tried and got nothing back.
         yield (
@@ -245,10 +241,7 @@ final albumProvider = StreamProvider.family<
         continue;
       }
       fetchAttempted = true;
-      final online = await isOnline();
+      if (!await isOnline()) {
-      debugPrint('albumProvider($albumId): online=$online');
-      if (!online) {
-        debugPrint('albumProvider($albumId): offline, yielding empty');
         yield (
           album: const AlbumRef(id: '', title: '', artistId: ''),
           tracks: const <TrackRef>[],
@@ -265,7 +258,6 @@ final albumProvider = StreamProvider.family<
       // On success, drift watch re-emits with rows; loop continues.
       continue;
     }
-    debugPrint('albumProvider($albumId): drift hit (${albumRows.length} rows)');
 
     final albumRow = albumRows.first;
     final album = albumRow.readTable(db.cachedAlbums).toRef(
@@ -280,7 +272,6 @@ final albumProvider = StreamProvider.family<
     // fetchAndPopulate so the album becomes complete; drift watch
     // re-emits and we land in the populated branch on the next pass.
     if (trackRows.isEmpty && !fetchAttempted) {
-      debugPrint('albumProvider($albumId): album hit but no tracks; fetching');
       fetchAttempted = true;
       if (await isOnline()) {
         final ok = await fetchAndPopulate();

flutter_client/lib/player/audio_handler.dart

@@ -33,15 +33,6 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
     // the index and the eviction loop can't reclaim them.
     _player.bufferedPositionStream
         .listen((_) => unawaited(_maybeRegisterStreamCache()));
-    // Diagnostic: log every player-state transition so silent stops
-    // surface as something we can read in the log.
-    _player.playerStateStream.listen((s) {
-      debugPrint(
-          'audio_handler: state playing=${s.playing} processing=${s.processingState}');
-    });
-    _player.processingStateStream.listen((ps) {
-      debugPrint('audio_handler: processingState=$ps');
-    });
   }
 
   final AudioPlayer _player = AudioPlayer();
@@ -100,10 +91,6 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
     _token = token;
     if (coverCache != null) _coverCache = coverCache;
     if (audioCacheManager != null) _audioCacheManager = audioCacheManager;
-    debugPrint('audio_handler.configure: baseUrl="$baseUrl" '
-        'tokenPresent=${token != null && token.isNotEmpty} '
-        'coverCachePresent=${_coverCache != null} '
-        'audioCachePresent=${_audioCacheManager != null}');
   }
 
   Future<void> setQueueFromTracks(List<TrackRef> tracks, {int initialIndex = 0}) async {
@@ -127,10 +114,6 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
     queue.add(items);
     mediaItem.add(items[clampedInitial]);
 
-    debugPrint('audio_handler.setQueueFromTracks: '
-        '_baseUrl="$_baseUrl" trackCount=${tracks.length} gen=$myGen');
-    final sw = Stopwatch()..start();
-
     // Fast path: build only the initial source so the player can
     // start. Remaining sources stream in via _fillRemainingSources()
     // in the background — addAudioSource for next/auto-advance
@@ -140,13 +123,8 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
       debugPrint('audio_handler: superseded before setAudioSources (gen=$myGen)');
       return;
     }
-    debugPrint('audio_handler: built initial source in '
-        '${sw.elapsedMilliseconds}ms');
-    sw.reset();
-    sw.start();
 
     await _player.setAudioSources([initial], initialIndex: 0);
-    debugPrint('audio_handler: setAudioSources(1) ${sw.elapsedMilliseconds}ms');
 
     unawaited(_loadArtForCurrentItem());
     unawaited(_fillRemainingSources(tracks, clampedInitial, myGen));
@@ -166,12 +144,8 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
   /// addAudioSource calls from this stale fill.
   Future<void> _fillRemainingSources(
       List<TrackRef> tracks, int initialIndex, int gen) async {
-    final sw = Stopwatch()..start();
     for (var i = initialIndex + 1; i < tracks.length; i++) {
-      if (gen != _queueGeneration) {
+      if (gen != _queueGeneration) return;
-        debugPrint('audio_handler: forward fill aborted (gen=$gen, current=$_queueGeneration)');
-        return;
-      }
       try {
         final src = await _buildAudioSource(tracks[i]);
         if (gen != _queueGeneration) return;
@@ -180,18 +154,11 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
         debugPrint('audio_handler: forward fill failed for ${tracks[i].id}: $e');
       }
     }
-    debugPrint('audio_handler: forward fill (${tracks.length - initialIndex - 1}) '
-        '${sw.elapsedMilliseconds}ms');
     if (initialIndex > 0) {
-      sw.reset();
-      sw.start();
       _suppressIndexUpdates = true;
       try {
         for (var i = 0; i < initialIndex; i++) {
-          if (gen != _queueGeneration) {
+          if (gen != _queueGeneration) return;
-            debugPrint('audio_handler: backward fill aborted (gen=$gen, current=$_queueGeneration)');
-            return;
-          }
           final src = await _buildAudioSource(tracks[i]);
           if (gen != _queueGeneration) return;
           await _player.insertAudioSource(i, src);
@@ -203,8 +170,6 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
         // newer setQueueFromTracks already reset it for itself.
         if (gen == _queueGeneration) _suppressIndexUpdates = false;
       }
-      debugPrint('audio_handler: backward fill ($initialIndex) '
-          '${sw.elapsedMilliseconds}ms');
     }
   }
 
@@ -234,7 +199,6 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
     if (mgr != null) {
       final path = await mgr.pathFor(t.id);
       if (path != null) {
-        debugPrint('audio_handler: cache hit for track.id=${t.id} → file://$path');
         return AudioSource.uri(Uri.file(path));
       }
     }
@@ -260,15 +224,12 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
     if (mgr != null) {
       _cacheDirPath ??= (await getApplicationCacheDirectory()).path;
       final cacheFile = File('${_cacheDirPath!}/audio_cache/${t.id}.mp3');
-      debugPrint('audio_handler: cache miss for track.id=${t.id}, '
-          'using LockCachingAudioSource → ${cacheFile.path}');
       // ignore: experimental_member_use
       return LockCachingAudioSource(parsed,
           headers: headers, cacheFile: cacheFile);
     }
 
     // 3. No manager configured: plain network source (legacy path).
-    debugPrint('audio_handler: no cache manager; track.id=${t.id} → "$url"');
     return AudioSource.uri(parsed, headers: headers);
   }
 
@@ -344,8 +305,6 @@ class MinstrelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandl
 
     _streamCacheRegistered.add(trackId);
     await mgr.registerStreamCache(trackId, path, size);
-    debugPrint(
-        'audio_handler: registered stream cache for $trackId ($size bytes)');
   }
 
   void _onCurrentIndexChanged(int? idx) {

flutter_client/lib/player/player_provider.dart

@@ -1,5 +1,4 @@
 import 'package:audio_service/audio_service.dart';
-import 'package:flutter/foundation.dart' show debugPrint;
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../api/endpoints/radio.dart';
@@ -54,22 +53,8 @@ class PlayerActions {
   final Ref _ref;
 
   Future<void> playTracks(List<TrackRef> tracks, {int initialIndex = 0}) async {
-    // Stage-by-stage timing so we can see exactly where the
-    // "tap → audio" delay lives. Look for "playTracks: ..." lines
-    // in the next log capture; each stage label is followed by its
-    // elapsed millis since the previous stage.
-    final sw = Stopwatch()..start();
-    int lap() {
-      final ms = sw.elapsedMilliseconds;
-      sw.reset();
-      sw.start();
-      return ms;
-    }
-
     final url   = await _ref.read(serverUrlProvider.future);
-    debugPrint('playTracks: serverUrl ${lap()}ms');
     final token = await _ref.read(secureStorageProvider).read(key: 'session_token');
-    debugPrint('playTracks: token ${lap()}ms');
     final cache = _ref.read(albumCoverCacheProvider);
     final audioCache = _ref.read(audioCacheManagerProvider);
     final h = _ref.read(audioHandlerProvider)
@@ -79,11 +64,8 @@ class PlayerActions {
         coverCache: cache,
         audioCacheManager: audioCache,
       );
-    debugPrint('playTracks: configure ${lap()}ms');
     await h.setQueueFromTracks(tracks, initialIndex: initialIndex);
-    debugPrint('playTracks: setQueue (${tracks.length} tracks) ${lap()}ms');
     await h.play();
-    debugPrint('playTracks: play() returned ${lap()}ms');
   }
 
   Future<void> playNext(TrackRef track) async {

flutter_client/lib/playlists/playlists_provider.dart

@@ -40,11 +40,6 @@ final playlistsListProvider =
     fetchAndPopulate: () async {
       final api = await ref.read(playlistsApiProvider.future);
       final fresh = await api.list(kind: kind);
-      final ownedSysCount =
-          fresh.owned.where((p) => p.systemVariant != null).length;
-      debugPrint(
-          'playlistsListProvider($kind): wire returned owned=${fresh.owned.length} '
-          '(system=$ownedSysCount) public=${fresh.public.length}');
 
       // Reconcile: BuildSystemPlaylists rotates system-playlist UUIDs
       // every rebuild, so insertOrReplace alone leaves stale rows in
@@ -81,13 +76,6 @@ final playlistsListProvider =
           .where((r) => r.userId != user.id && r.isPublic)
           .map((r) => r.toRef())
           .toList();
-      final ownedSys = owned.where((p) => p.isSystem).length;
-      final driftSys = filtered.where((r) => r.systemVariant != null).length;
-      debugPrint(
-          'playlistsListProvider($kind): drift rows=${rows.length} '
-          'filtered=${filtered.length} (system=$driftSys) '
-          'owned=${owned.length} (system=$ownedSys) pub=${pub.length} '
-          'userId=${user.id}');
       return PlaylistsList(owned: owned, public: pub);
     },
     isOnline: () async => (await ref
@@ -153,10 +141,7 @@ final playlistDetailProvider =
   Future<bool> fetchAndPopulate() async {
     try {
       final api = await ref.read(playlistsApiProvider.future);
-      debugPrint('playlistDetailProvider($id): calling get');
       final fresh = await api.get(id).timeout(const Duration(seconds: 10));
-      debugPrint(
-          'playlistDetailProvider($id): got ${fresh.tracks.length} tracks, writing');
 
       // Collect the track + artist + album rows referenced by these
       // playlist entries. Without writing the cachedTracks rows
@@ -262,8 +247,6 @@ final playlistDetailProvider =
           );
         }
       });
-      debugPrint(
-          'playlistDetailProvider($id): drift write done; awaiting watch re-emit');
       return true;
     } catch (e, st) {
       // 404 = the playlist row in drift is stale (BuildSystemPlaylists
@@ -272,8 +255,6 @@ final playlistDetailProvider =
       // stale row + its track positions so the home tile disappears
       // on next render and we don't keep trying.
       if (e is DioException && e.response?.statusCode == 404) {
-        debugPrint(
-            'playlistDetailProvider($id): server says 404, evicting stale drift rows');
         await db.batch((b) {
           b.deleteWhere(
               db.cachedPlaylistTracks, (t) => t.playlistId.equals(id));
@@ -292,7 +273,6 @@ final playlistDetailProvider =
 
   await for (final playlistRows in playlistQuery.watch()) {
     if (playlistRows.isEmpty) {
-      debugPrint('playlistDetailProvider($id): drift miss, cold-fetching');
       if (fetchAttempted) {
         yield emptyDetail();
         continue;
@@ -307,9 +287,6 @@ final playlistDetailProvider =
       continue;
     }
 
-    debugPrint(
-        'playlistDetailProvider($id): drift hit (${playlistRows.length} rows)');
-
     final playlist = playlistRows.first.toRef();
     final trackRows = await tracksQuery.get();
 
@@ -318,8 +295,6 @@ final playlistDetailProvider =
     // tracks for system playlists). Trigger the same fetch, drift
     // watch re-emits with populated tracks.
     if (trackRows.isEmpty && !fetchAttempted) {
-      debugPrint(
-          'playlistDetailProvider($id): playlist hit but no tracks; fetching');
       fetchAttempted = true;
       if (await isOnline()) {
         final ok = await fetchAndPopulate();