fix: 修复条件式 hook 调用导致的 "Rendered fewer hooks than expected" 错误

修复在 dev 模式下按下 Ctrl+O 切换 transcript 视图时 React 抛出
"Rendered fewer hooks than expected" 崩溃的问题。

## 根因分析

项目中有大量 hook（useState / useMemo / useRef / useSyncExternalStore 等）
被包裹在 `feature()` 三元表达式中条件调用，例如：

    const value = feature('X') ? useHook() : defaultValue;

在 build 模式下 `feature()` 是编译时常量，死代码消除会移除未使用的分支，
hooks 数量在编译后是确定的。但在 dev 模式下（scripts/dev.ts 注入
--feature 启用全部 31 个 feature），`feature()` 是运行时调用，
但始终返回 true，因此所有 hooks 都会被调用，原本不会出问题。

真正的触发器是 REPL.tsx 第 5381 行的提前返回：

    if (screen === 'transcript') { return transcriptReturn; }

当用户按下 Ctrl+O 进入 transcript 模式时，该提前返回之后的所有 hooks
（如 displayedAgentMessages 的 useMemo）都不会被调用，导致 React 在
下一次渲染时检测到 hooks 数量与上次不一致而崩溃。

此外，其他文件中也存在相同的条件式 hook 模式——虽然 dev 模式下
feature() 返回 true，所以这些路径实际上不会被触发，但它们是
潜在的隐患：若将来有人通过环境变量关闭某个 feature，
同样的崩溃会立即出现。

## 修复策略

采用统一模式：**始终无条件调用 hook，将 feature() gate 应用到值上**。

    // Before (unsafe — hook count varies by feature flag)
    const value = feature('X') ? useHook() : defaultValue;

    // After (safe — hook always called, gate on the value)
    const rawValue = useHook();
    const value = feature('X') ? rawValue : defaultValue;

## 修改清单

### 核心修复（REPL.tsx）
- 将 `displayedAgentMessages` useMemo 及依赖变量（viewedTask /
  viewedTeammateTask / viewedAgentTask / usesSyncMessages /
  rawAgentMessages / displayedMessages）从 transcript 提前返回
  之后移至之前，确保两模式下 hooks 调用顺序一致
- 修复 `disableMessageActions` / `useAssistantHistory` /
  `voiceIntegration` 的条件式 hook 调用

### 条件式 hook 修复（11 个文件）
- src/hooks/useGlobalKeybindings.tsx — isBriefOnly / toggleBrief
  keybinding 改为 isActive 门控
- src/hooks/useReplBridge.tsx — 5 个 BRIDGE_MODE 选值改为无条件调用
- src/hooks/useVoiceIntegration.tsx — 4 个 VOICE_MODE 选值修复
- src/components/PromptInput/Notifications.tsx — 4 个 feature 选值修复
- src/components/PromptInput/PromptInput.tsx — briefOwnsGap /
  companionSpeaking 修复
- src/components/PromptInput/PromptInputFooterLeftSide.tsx — 4 个
  VOICE_MODE 选值修复
- src/components/PromptInput/PromptInputQueuedCommands.tsx — isBriefOnly
- src/components/Spinner.tsx — briefEnvEnabled 修复
- src/components/TextInput.tsx — voiceState / audioLevels /
  animationFrame 修复
- src/components/messages/AttachmentMessage.tsx — isDemoEnv 修复
- src/components/messages/UserPromptMessage.tsx — isBriefOnly /
  viewingAgentTaskId / briefEnvEnabled 修复
- src/components/messages/UserToolResultMessage/UserToolSuccessMessage.tsx
  — isBriefOnly 修复

### 其他修复
- src/components/FeedbackSurvey/useFrustrationDetection.ts — 将 3 个
  提前返回合并为 shouldSkip 变量，handleTranscriptSelect 提前 return
- src/hooks/useIssueFlagBanner.ts — useRef 移到 USER_TYPE 检查之前
- src/hooks/useUpdateNotification.ts — useState 改为 useRef，
  避免版本号变化触发不必要重渲染

### 构建/开发配置
- build.ts — 添加 `sourcemap: 'linked'`
- scripts/dev.ts — NODE_ENV 从 'production' 改为 'development'

Closes #434

src/hooks/useGlobalKeybindings.tsx

@@ -83,7 +83,7 @@ export function GlobalKeybindingHandlers({
 
   // Toggle transcript mode (ctrl+o). Two-way prompt ↔ transcript.
   // Brief view has its own dedicated toggle on ctrl+shift+b.
-  const isBriefOnly = feature('KAIROS') || feature('KAIROS_BRIEF') ? useAppState(s => s.isBriefOnly) : false;
+  const isBriefOnlyState = useAppState(s => s.isBriefOnly);
   const handleToggleTranscript = useCallback(() => {
     if (feature('KAIROS') || feature('KAIROS_BRIEF')) {
       // Escape hatch: GB kill-switch while defaultView=chat was persisted
@@ -95,7 +95,7 @@ export function GlobalKeybindingHandlers({
       const { isBriefEnabled } =
         require('@claude-code-best/builtin-tools/tools/BriefTool/BriefTool.js') as typeof import('@claude-code-best/builtin-tools/tools/BriefTool/BriefTool.js');
       /* eslint-enable @typescript-eslint/no-require-imports */
-      if (!isBriefEnabled() && isBriefOnly && screen !== 'transcript') {
+      if (!isBriefEnabled() && isBriefOnlyState && screen !== 'transcript') {
         setAppState(prev => {
           if (!prev.isBriefOnly) return prev;
           return { ...prev, isBriefOnly: false };
@@ -121,7 +121,7 @@ export function GlobalKeybindingHandlers({
   }, [
     screen,
     setScreen,
-    isBriefOnly,
+    isBriefOnlyState,
     showAllInTranscript,
     setShowAllInTranscript,
     messageCount,
@@ -162,8 +162,8 @@ export function GlobalKeybindingHandlers({
       const { isBriefEnabled } =
         require('@claude-code-best/builtin-tools/tools/BriefTool/BriefTool.js') as typeof import('@claude-code-best/builtin-tools/tools/BriefTool/BriefTool.js');
       /* eslint-enable @typescript-eslint/no-require-imports */
-      if (!isBriefEnabled() && !isBriefOnly) return;
-      const next = !isBriefOnly;
+      if (!isBriefEnabled() && !isBriefOnlyState) return;
+      const next = !isBriefOnlyState;
       logEvent('tengu_brief_mode_toggled', {
         enabled: next,
         gated: false,
@@ -174,7 +174,7 @@ export function GlobalKeybindingHandlers({
         return { ...prev, isBriefOnly: next };
       });
     }
-  }, [isBriefOnly, setAppState]);
+  }, [isBriefOnlyState, setAppState]);
 
   // Register keybinding handlers
   useKeybinding('app:toggleTodos', handleToggleTodos, {
@@ -183,11 +183,10 @@ export function GlobalKeybindingHandlers({
   useKeybinding('app:toggleTranscript', handleToggleTranscript, {
     context: 'Global',
   });
-  if (feature('KAIROS') || feature('KAIROS_BRIEF')) {
-    useKeybinding('app:toggleBrief', handleToggleBrief, {
-      context: 'Global',
-    });
-  }
+  useKeybinding('app:toggleBrief', handleToggleBrief, {
+    context: 'Global',
+    isActive: feature('KAIROS') ? true : feature('KAIROS_BRIEF') ? true : false,
+  });
 
   // Register teammate keybinding
   useKeybinding(