优化: UI/UX遗留批(审计/AI命令层/前端组件,会话前基线收尾)

- AuditLog +298(筛选/详情/i18n)+ audit 后端 record/mod

- AI 命令层:generate_image +81 / fetch_url / fetch_search / skills / tool_registry / tools/file / provider / conversation

- 前端组件:AiChat/TopBar/ConversationSidebar/GitChanges/ApprovalPopup/Dashboard/ProjectDetail 等 30+ + composables + i18n

- 诊断文档: aichat历史会话实证诊断-2026-08-04 + project_soft_delete 测试

src/components/layout/AppSidebar.vue

@@ -68,8 +68,8 @@
       <!-- 7b:收缩/展开切换按钮(最底部,快捷键 Ctrl+B 同效) -->
       <button class="nav-link collapse-toggle-btn" @click="toggleCollapsed" :title="collapsed ? $t('nav.expand') : $t('nav.collapse')">
         <span class="nav-link-icon">
-          <svg v-if="!collapsed" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><polyline points="15 18 9 12 15 6"/></svg>
-          <svg v-else width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><polyline points="9 18 15 12 9 6"/></svg>
+          <svg v-if="!collapsed" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><polyline points="15 18 9 12 15 6"/></svg>
+          <svg v-else width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><polyline points="9 18 15 12 9 6"/></svg>
         </span>
         <span v-if="!collapsed" class="nav-link-text">{{ $t('nav.collapse') }}</span>
         <span v-if="!collapsed" class="ai-toggle-shortcut">Ctrl+B</span>
@@ -150,7 +150,7 @@ const secondaryNav = [
   { path: '/knowledge', label: 'nav.knowledge',
     svg: '<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><path d="M4 19.5A2.5 2.5 0 016.5 17H20"/><path d="M6.5 2H20v20H6.5A2.5 2.5 0 014 19.5v-15A2.5 2.5 0 016.5 2z"/></svg>' },
   { path: '/audit', label: 'nav.audit',
-    svg: '<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><path d="M9 11l3 3L22 4"/><path d="M21 12v7a2 2 0 01-2 2H5a2 2 0 01-2-2V5a2 2 0 012-2h11"/></svg>' },
+    svg: '<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"/><polyline points="12 6 12 12 16 14"/></svg>' },
 ]
 </script>