performance improvements

apps/weblibre/lib/features/proxy/domain/repositories/singbox_proxy_logs.dart

@@ -33,7 +33,20 @@ part 'singbox_proxy_logs.g.dart';
 /// is well within budget for a debugging surface.
 const int _ringBufferCapacity = 2000;
 
+/// Lower bound between two published snapshots. A chatty proxy can emit lines
+/// far faster than the screen can render them, and every publication copies the
+/// whole ring buffer, so coalescing bursts is free in terms of what the user
+/// actually sees.
+const _publishInterval = Duration(milliseconds: 100);
+
 /// Snapshot of buffered log entries. Most-recent-last (chronological).
+///
+/// This notifier is `keepAlive` and subscribed from app start (see
+/// `main.dart`) so startup messages are retained even before any UI mounts.
+/// Appending and *publishing* are therefore deliberately decoupled: lines
+/// always land in [_buffer], but a new immutable snapshot is only produced
+/// while the log screen is on screen ([setLivePublishing]) and at most once
+/// per [_publishInterval].
 @Riverpod(keepAlive: true)
 class SingboxProxyLogs extends _$SingboxProxyLogs {
   final _buffer = Queue<ProxyLogMessage>();
@@ -41,6 +54,28 @@ class SingboxProxyLogs extends _$SingboxProxyLogs {
   StreamSubscription<SingboxProxyLogMessage>? _singboxSubscription;
   StreamSubscription<TorLogMessage>? _torSubscription;
 
+  Timer? _publishTimer;
+  bool _livePublishing = false;
+
+  /// Buffer contents materialized on demand, regardless of publication state.
+  /// Lets a freshly mounted screen paint the backlog without waiting for the
+  /// first throttled snapshot.
+  List<ProxyLogMessage> get snapshot => List.unmodifiable(_buffer);
+
+  /// Enables/disables snapshot publication. Called by the log screen as it
+  /// mounts and unmounts; flushes on both edges so the state left behind is
+  /// always complete.
+  void setLivePublishing(bool enabled) {
+    if (_livePublishing == enabled) {
+      return;
+    }
+
+    _livePublishing = enabled;
+    _publishTimer?.cancel();
+    _publishTimer = null;
+    _publish();
+  }
+
   void _append(ProxyLogMessage message) {
     _buffer.add(message);
 
@@ -48,11 +83,27 @@ class SingboxProxyLogs extends _$SingboxProxyLogs {
       _buffer.removeFirst();
     }
 
-    state = List.unmodifiable(_buffer);
+    if (!_livePublishing || (_publishTimer?.isActive ?? false)) {
+      return;
+    }
+
+    _publishTimer = Timer(_publishInterval, _publish);
+  }
+
+  void _publish() {
+    _publishTimer = null;
+
+    if (!ref.mounted) {
+      return;
+    }
+
+    state = snapshot;
   }
 
   void clear() {
     _buffer.clear();
+    _publishTimer?.cancel();
+    _publishTimer = null;
     state = const [];
   }
 
@@ -69,10 +120,11 @@ class SingboxProxyLogs extends _$SingboxProxyLogs {
     );
 
     ref.onDispose(() {
+      _publishTimer?.cancel();
       unawaited(_singboxSubscription?.cancel());
       unawaited(_torSubscription?.cancel());
     });
 
-    return List.unmodifiable(_buffer);
+    return snapshot;
   }
 }