fix(ui): address PR #30 review findings

- ViewportInfo.updateShouldNotify: compare layoutClass only
  (not width/height), avoiding unnecessary rebuilds on every
  resize frame within the same layout class.
- ChatPanel: use BorderDirectional(start:) for RTL support.
- ChatPanel: localize 'Close chat' tooltip via AppL10n.chatCloseAction.
- Inline panel snackbar: localize via AppL10n.chatPanelCollapsedHint.
  New en/zh ARB entries added.
- _saveCurrentDraft(): removed — it was a self-assignment no-op.
  Draft persistence relies on ChatDetailView's didUpdateWidget
  (fires onDraftChanged on target switch) and dispose (fires on
  panel tear-down), both of which already populate _chatDrafts
  correctly without an explicit save call.
- _handleInlineChatViewport layout snackbar: use AppL10n.
- Audio level-meter: switch from callback-count (% 3) to time-based
  gating (std::time::Duration::from_millis(33)), robust to cpal
  buffer-size or sample-rate changes. Remove level_decimation_counter.
- chat_panel_test.dart: add AppL10n.localizationsDelegates so the
  test resolves l10n keys.

Tests: 183 passed, 2 skipped. Dart analyze clean.
cargo test -p chanora_audio --lib: 125 passed.

apps/chanora_flutter/lib/design/viewport_info.dart

@@ -57,8 +57,11 @@ class ViewportInfo extends InheritedWidget {
   bool get isWide => !isCompact;
 
   @override
-  bool updateShouldNotify(ViewportInfo old) =>
+  bool updateShouldNotify(ViewportInfo old) => layoutClass != old.layoutClass;
-      layoutClass != old.layoutClass ||
+  // NOTE: width/height changes within the same layout class do NOT trigger
-      width != old.width ||
+  // notification. Dependents who genuinely need pixel-level dimensions
-      height != old.height;
+  // (rare — most layouts should switch on layoutClass) must use a local
+  // LayoutBuilder. Notifying on every pixel would rebuild every dependent
+  // on every resize frame, which is the exact pessimisation this
+  // InheritedWidget exists to avoid.
 }

apps/chanora_flutter/lib/l10n/app_en.arb

@@ -46,6 +46,7 @@
   "retryAction": "Retry",
   "chatAction": "Chat",
   "chatCloseAction": "Close chat",
+  "chatPanelCollapsedHint": "Tap the chat button to continue your conversation",
   "chatNewPrivateAction": "New private chat",
   "chatSearchClientsHint": "Search clients...",
   "chatDirectMessageAction": "Private message",

apps/chanora_flutter/lib/l10n/app_zh.arb

@@ -39,6 +39,7 @@
   "retryAction": "重试",
   "chatAction": "聊天",
   "chatCloseAction": "关闭聊天",
+  "chatPanelCollapsedHint": "点击聊天按钮以继续对话",
   "chatNewPrivateAction": "新建私聊",
   "chatSearchClientsHint": "搜索用户...",
   "chatDirectMessageAction": "私聊",

apps/chanora_flutter/lib/l10n/generated/app_localizations.dart

@@ -307,6 +307,12 @@ abstract class AppL10n {
   /// **'Close chat'**
   String get chatCloseAction;
 
+  /// No description provided for @chatPanelCollapsedHint.
+  ///
+  /// In en, this message translates to:
+  /// **'Tap the chat button to continue your conversation'**
+  String get chatPanelCollapsedHint;
+
   /// No description provided for @chatNewPrivateAction.
   ///
   /// In en, this message translates to:

apps/chanora_flutter/lib/l10n/generated/app_localizations_en.dart

@@ -123,6 +123,10 @@ class AppL10nEn extends AppL10n {
   @override
   String get chatCloseAction => 'Close chat';
 
+  @override
+  String get chatPanelCollapsedHint =>
+      'Tap the chat button to continue your conversation';
+
   @override
   String get chatNewPrivateAction => 'New private chat';
 

apps/chanora_flutter/lib/l10n/generated/app_localizations_zh.dart

@@ -120,6 +120,9 @@ class AppL10nZh extends AppL10n {
   @override
   String get chatCloseAction => '关闭聊天';
 
+  @override
+  String get chatPanelCollapsedHint => '点击聊天按钮以继续对话';
+
   @override
   String get chatNewPrivateAction => '新建私聊';
 

apps/chanora_flutter/lib/main.dart

@@ -1673,17 +1673,18 @@ class _BetaHomeState extends State<_BetaHome> with WidgetsBindingObserver {
     };
   }
 
-  /// Saves the current draft text for the current inline chat target.
+  /// Returns the current draft text for the inline chat target, or null
-  void _saveCurrentDraft() {
+  /// if no draft has been stored.
-    // Drafts are continuously saved via onDraftChanged callback in Task 4.
+  ///
-    // This method exists as an explicit save point.
+  /// Draft persistence relies on [ChatDetailView]'s own lifecycle:
-    final target = _inlineChatTarget;
+  /// `didUpdateWidget` flushes the outgoing target's draft via
-    if (target == null) return;
+  /// `onDraftChanged` when the parent rebuilds with a new target, and
-    final key = _draftKeyForTarget(target);
+  /// `dispose` flushes the final draft when the panel is torn down
-    if (_chatDrafts.containsKey(key)) {
+  /// (e.g. on [_closeInlineChat]). Both paths feed
-      _chatDrafts[key] = _chatDrafts[key] ?? '';
+  /// [_chatDrafts] without requiring an explicit save call from this
-    }
+  /// class.
-  }
+  String? _currentDraftFor(rust.BridgeMessageTarget target) =>
+      _chatDrafts[_draftKeyForTarget(target)];
 
   Future<void> _onOpenChat({
     rust.BridgeMessageTarget? target,
@@ -1722,8 +1723,9 @@ class _BetaHomeState extends State<_BetaHome> with WidgetsBindingObserver {
         layoutClassFromWidth(MediaQuery.sizeOf(context).width) ==
         LayoutClass.expanded;
     if (isExpanded) {
+      // Outgoing draft is preserved by ChatDetailView.didUpdateWidget,
+      // which fires onDraftChanged with the old target's text on rebuild.
       setState(() {
-        _saveCurrentDraft();
         _chatUnread = 0;
         _chatOpen = true;
         _inlineChatTarget = newTarget;
@@ -1754,8 +1756,10 @@ class _BetaHomeState extends State<_BetaHome> with WidgetsBindingObserver {
   }
 
   void _closeInlineChat() {
+    // Final draft for the dismissed target is preserved by
+    // ChatDetailView.dispose, which fires onDraftChanged when the panel
+    // is removed from the tree on the next rebuild.
     setState(() {
-      _saveCurrentDraft();
       _lastDismissedTarget = _inlineChatTarget;
       _lastDismissedClientName = _inlineChatClientName;
       _chatOpen = false;
@@ -1788,8 +1792,8 @@ class _BetaHomeState extends State<_BetaHome> with WidgetsBindingObserver {
     WidgetsBinding.instance.addPostFrameCallback((_) {
       if (!mounted || _inlineChatTarget == null) return;
       ScaffoldMessenger.of(context).showSnackBar(
-        const SnackBar(
+        SnackBar(
-          content: Text('Tap the chat button to continue your conversation'),
+          content: Text(AppL10n.of(context).chatPanelCollapsedHint),
         ),
       );
     });
@@ -2654,10 +2658,9 @@ class _BetaHomeState extends State<_BetaHome> with WidgetsBindingObserver {
                                 snapshot: _snapshot!,
                                 target: inlineChatTarget,
                                 clientName: _inlineChatClientName,
-                                restoredDraft:
+                                restoredDraft: _currentDraftFor(
-                                    _chatDrafts[_draftKeyForTarget(
+                                  inlineChatTarget,
-                                      inlineChatTarget,
+                                ),
-                                    )],
                                 onDraftChanged: (text) {
                                   final draftKey = _draftKeyForTarget(
                                     inlineChatTarget,

apps/chanora_flutter/lib/widgets/chat_panel.dart

@@ -3,6 +3,7 @@
 import 'package:flutter/material.dart';
 
 import '../design/breakpoints.dart';
+import '../l10n/generated/app_localizations.dart';
 import '../services/snapshot_state_mapper.dart';
 import '../services/ts3_server_link.dart';
 import '../src/rust/api.dart' as rust;
@@ -51,14 +52,15 @@ class ChatPanel extends StatelessWidget {
   Widget build(BuildContext context) {
     final currentChannelId = ownClientSnapshotState(snapshot)?.channelId;
     final channelName = snapshotChannelName(snapshot, currentChannelId);
+    final l10n = AppL10n.of(context);
 
     return SizedBox(
       width: ChanoraBreakpoints.chatPanelWidth,
       child: DecoratedBox(
         decoration: BoxDecoration(
           color: Theme.of(context).colorScheme.surface,
-          border: Border(
+          border: BorderDirectional(
-            left: BorderSide(
+            start: BorderSide(
               color: Theme.of(context).colorScheme.outlineVariant,
             ),
           ),
@@ -75,7 +77,7 @@ class ChatPanel extends StatelessWidget {
           onDraftChanged: onDraftChanged,
           messageMaxWidth: 500,
           headerTrailing: IconButton(
-            tooltip: 'Close chat',
+            tooltip: l10n.chatCloseAction,
             icon: const Icon(Icons.close),
             onPressed: onClose,
           ),

apps/chanora_flutter/test/widgets/chat_panel_test.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import 'package:chanora_flutter/l10n/generated/app_localizations.dart';
 import 'package:chanora_flutter/src/rust/api.dart' as rust;
 import 'package:chanora_flutter/widgets/chat_panel.dart';
 import 'package:chanora_flutter/widgets/chat_views.dart';
@@ -55,6 +56,8 @@ void main() {
 
     await tester.pumpWidget(
       MaterialApp(
+        localizationsDelegates: AppL10n.localizationsDelegates,
+        supportedLocales: AppL10n.supportedLocales,
         home: Scaffold(
           body: ChatPanel(
             messages: messages,
@@ -87,6 +90,8 @@ void main() {
       required String? restoredDraft,
     }) {
       return MaterialApp(
+        localizationsDelegates: AppL10n.localizationsDelegates,
+        supportedLocales: AppL10n.supportedLocales,
         home: Scaffold(
           body: ChatDetailView(
             messages: messages,

crates/chanora_audio/src/engine.rs

@@ -1818,18 +1818,27 @@ struct CaptureState {
     /// after warmup. Same precedent as `mono_scratch` above.
     frame_scratch: Vec<f32>,
     audio_processing_stats: Arc<crate::SharedAudioProcessingStats>,
-    /// Decimation counter for the level meter. The cpal callback fires
+    /// Time-based decimation for the level meter. The cpal callback
-    /// ~93 times/sec (256 frames at 48 kHz), but the bridge consumer
+    /// cadence depends on platform (256 frames at 48 kHz ≈ 187 Hz,
-    /// (`input_level_stream`) only reads at ~30 Hz. Computing `sqrt()`
+    /// 512 frames ≈ 94 Hz, 1024 frames ≈ 47 Hz) and can change at
-    /// + `log10()` every callback wastes real-time budget and causes
+    /// runtime on device or sample-rate switch. The bridge consumer
-    /// buffer underruns on macOS CoreAudio. We accumulate the running
+    /// (`input_level_stream`) only reads at ~30 Hz, so computing
-    /// sum-of-squares every callback (trivially cheap: O(n) multiply-
+    /// `sqrt()` + `log10()` on every callback wastes real-time budget
-    /// add) and only compute the final dBFS every 3rd callback (~31 Hz),
+    /// and caused buffer underruns on macOS CoreAudio with small
-    /// matching the consumer rate. See commit history for the metering
+    /// buffer sizes. We only emit a new dBFS sample after at least
-    /// regression that motivated this.
+    /// [LEVEL_METER_INTERVAL] has elapsed since the previous emit,
-    level_decimation_counter: u32,
+    /// which is platform-cadence-independent.
+    last_level_emit: std::time::Instant,
 }
 
+/// Minimum interval between input-level dBFS samples sent to the
+/// bridge. Matches the consumer rate (`input_level_stream` at ~30 Hz).
+/// Time-based gating is robust to cpal buffer-size and sample-rate
+/// changes that a fixed callback-count would not be.
+#[cfg(not(any(target_os = "ios", target_os = "macos", target_os = "android")))]
+const LEVEL_METER_INTERVAL: std::time::Duration =
+    std::time::Duration::from_millis(33);
+
 #[cfg(not(any(target_os = "ios", target_os = "macos", target_os = "android")))]
 impl CaptureState {
     fn new(
@@ -1857,7 +1866,10 @@ impl CaptureState {
             mono_scratch: Vec::with_capacity(4096),
             frame_scratch: Vec::with_capacity(FRAME_SAMPLES),
             audio_processing_stats,
-            level_decimation_counter: 0,
+            // Start in the past so the first ingest emits immediately.
+            last_level_emit: std::time::Instant::now()
+                .checked_sub(LEVEL_METER_INTERVAL)
+                .unwrap_or_else(std::time::Instant::now),
         }
     }
 
@@ -1877,11 +1889,12 @@ impl CaptureState {
             self.mono_scratch.push(sum / frame.len() as f32);
         }
 
-        // Level meter: accumulate sum-of-squares on every callback
+        // Level meter: pay sqrt() + log10() only when at least
-        // (trivially cheap), but only pay for sqrt() + log10() every
+        // LEVEL_METER_INTERVAL has elapsed, regardless of the
-        // 3rd callback (~31 Hz, matching the bridge consumer rate).
+        // platform's cpal callback cadence.
-        self.level_decimation_counter = self.level_decimation_counter.wrapping_add(1);
+        let now = std::time::Instant::now();
-        if self.level_decimation_counter % 3 == 0 {
+        if now.duration_since(self.last_level_emit) >= LEVEL_METER_INTERVAL {
+            self.last_level_emit = now;
             self.audio_processing_stats
                 .set_input_dbfs(crate::frame::dbfs(&self.mono_scratch));
         }