新增: Phase2 阶段收尾（Sprint 1-20）

重构：删 5 零引用 crate（df-evolve/plugin/stages/task/traceability）+ 清死模块、ai.rs 拆 11 子 module、ai.ts 拆 6 composable、i18n 拆目录
功能：知识库全栈（df-project/scan + CRUD + 时间线 + 前端）、Settings 拆分、appSettings KV 迁移、模型池、LLM 并发 Semaphore
修复：审批持久化根治、ConditionEngine 默认拒绝、NodeRegistry unimplemented 清除、promote 补偿删除、工具结果截断 50KB、路径校验防 symlink 逃逸
文档：B-03 人工审批设计、决策记录三分档、规格契约自检、经验记录、todo 看板、PROGRESS 更新

详见 PROGRESS.md。src-tauri/儿童每日打卡应用/ 与本项目无关，已排除。

src/App.vue

@@ -51,6 +51,7 @@
           >
             <span class="nav-link-icon" v-html="item.svg"></span>
             <span class="nav-link-text">{{ $t(item.label) }}</span>
+            <span v-if="item.path === '/knowledge' && candidateCount > 0" class="nav-link-badge">{{ candidateCount }}</span>
           </router-link>
         </div>
       </nav>
@@ -79,7 +80,8 @@
     </aside>
 
     <!-- ═══ Main (页面内容) ═══ -->
-    <main class="df-main" v-show="!aiStore.state.maximized">
+    <!-- 仅在 AI 面板可见且最大化时隐藏主内容；面板关闭时无论 maximized 状态如何都显示 -->
+    <main class="df-main" v-show="!(aiStore.state.maximized && aiStore.state.panelOpen)">
       <router-view v-slot="{ Component }">
         <transition name="page" mode="out-in">
           <component :is="Component" />
@@ -95,17 +97,39 @@
       </div>
     </transition>
   </div>
+
+  <!-- 全局错误 toast(根级,主窗口与分离窗口共用)-->
+  <transition name="toast">
+    <div v-if="errorMsg" class="df-toast">⚠ {{ errorMsg }}</div>
+  </transition>
 </template>
 
 <script setup lang="ts">
 import { ref, computed, watch, onMounted, onUnmounted } from 'vue'
 import { useRoute } from 'vue-router'
 import { useAiStore } from './stores/ai'
+import { useKnowledgeStore } from './stores/knowledge'
+import { useProjectStore } from './stores/project'
+import { useAppSettingsStore } from './stores/appSettings'
+import i18n from './i18n'
 import AiChat from './components/AiChat.vue'
 
 const route = useRoute()
 const isDetached = computed(() => route.path === '/ai-detached')
 const aiStore = useAiStore()
+const appSettings = useAppSettingsStore()
+
+// ── 全局错误 toast(消费 projectStore.error,所有 action 失败统一反馈)──
+const projectStore = useProjectStore()
+const errorMsg = ref('')
+let errorTimer: ReturnType<typeof setTimeout> | null = null
+watch(() => projectStore.error, (err) => {
+  if (!err) return
+  errorMsg.value = err
+  projectStore.clearError() // 重置,允许连续同值错误再次触发
+  if (errorTimer) clearTimeout(errorTimer)
+  errorTimer = setTimeout(() => { errorMsg.value = '' }, 3500)
+})
 
 // 点击菜单自动退出最大化 → 切为分栏模式
 watch(() => route.path, (path) => {
@@ -115,7 +139,8 @@ watch(() => route.path, (path) => {
 })
 
 // ── AI 面板拖拽调宽 ──
-const panelWidth = ref(parseInt(localStorage.getItem('df-ai-width') || '500', 10))
+// useSetting 监听 appSettings 缓存:loadAll 异步填充后会自动刷新 ref
+const panelWidth = appSettings.useSetting<number>('df-ai-width', 500)
 const resizing = ref(false)
 
 // maximized=全宽(flex:1填充) | sidebar=固定宽
@@ -147,7 +172,7 @@ function startResize(e: MouseEvent) {
     resizing.value = false
     document.body.style.cursor = ''
     document.body.style.userSelect = ''
-    localStorage.setItem('df-ai-width', String(panelWidth.value))
+    void appSettings.set('df-ai-width', panelWidth.value)
     document.removeEventListener('mousemove', onMouseMove)
     document.removeEventListener('mouseup', onMouseUp)
   }
@@ -158,7 +183,7 @@ function startResize(e: MouseEvent) {
 
 // 主题初始化
 function initTheme() {
-  const saved = localStorage.getItem('df-theme') || 'dark'
+  const saved = appSettings.get<string>('df-theme', 'dark')
   if (saved === 'light') {
     document.documentElement.setAttribute('data-theme', 'light')
   } else if (saved === 'system') {
@@ -175,11 +200,58 @@ function handleKeydown(e: KeyboardEvent) {
   }
 }
 
-onMounted(() => {
+onMounted(async () => {
+  // 1. 先把 SQLite 全表 KV 填进 appSettings 缓存(后续 get/useSetting 才能读到真实值)
+  await appSettings.loadAll()
+  // 2. 一次性迁移:把旧 localStorage 的 11 个 key 导入 SQLite(仅首次跑,之后 localStorage 清净)
+  await migrateLegacyLocalStorage()
+  // 3. 缓存已就绪,初始化主题/locale
   initTheme()
+  const savedLang = appSettings.get<string | null>('df-language', null)
+  if (savedLang) {
+    i18n.global.locale.value = savedLang as 'zh-CN' | 'en'
+  }
   window.addEventListener('keydown', handleKeydown)
+  // 加载知识库候选数(供侧栏 knowledge badge 显示)
+  knowledgeStore.loadCandidates()
 })
 
+/// 一次性迁移:遍历遗留的 localStorage key,若有值则导入 appSettings(SQLite),
+/// 然后删除 localStorage 中的旧 key。导入时按各 key 原存格式解析成 JS 值再交给 set
+/// (set 内部会 JSON.stringify)。之后 localStorage 只剩 df-ai-gen / df-ai-text 流式快照。
+const LEGACY_KEYS_RAW = new Set(['df-theme', 'df-language', 'df-ai-language']) // 裸字符串
+const LEGACY_KEYS_JSON = new Set([ // 已 JSON.stringify(裸值或对象)
+  'df-ai-width', 'df-ai-ui', 'df-show-token-usage',
+  'df-llm-global-concurrency', 'df-llm-per-conv-concurrency',
+  'df-ai-active-conv', 'df-connections',
+])
+function parseLegacy(key: string, raw: string): unknown {
+  if (LEGACY_KEYS_RAW.has(key)) return raw // 裸字符串,如 'dark' / 'zh-CN'
+  // JSON 类:有的存的是 JSON.stringify('zh-CN') → '"zh-CN"'(虽不在本集合,保险起见 parse)
+  try {
+    return JSON.parse(raw)
+  } catch {
+    return raw
+  }
+}
+async function migrateLegacyLocalStorage(): Promise<void> {
+  const allKeys = [...LEGACY_KEYS_RAW, ...LEGACY_KEYS_JSON]
+  for (const key of allKeys) {
+    const raw = localStorage.getItem(key)
+    if (raw === null || raw === '') continue
+    try {
+      await appSettings.set(key, parseLegacy(key, raw))
+    } catch (e) {
+      console.error(`[migrate] 导入 ${key} 失败:`, e)
+    }
+    localStorage.removeItem(key)
+  }
+}
+
+// 知识库候选数量(侧栏 badge)— 解包 computed 取值保持响应式
+const knowledgeStore = useKnowledgeStore()
+const candidateCount = computed(() => knowledgeStore.candidateCount)
+
 onUnmounted(() => {
   window.removeEventListener('keydown', handleKeydown)
 })
@@ -437,4 +509,15 @@ const secondaryNav = [
 .page-leave-active { transition: opacity 0.12s var(--df-ease), transform 0.12s var(--df-ease); }
 .page-enter-from { opacity: 0; transform: translateY(6px); }
 .page-leave-to { opacity: 0; transform: translateY(-4px); }
+
+/* ═══ 全局错误 toast ═══ */
+.df-toast {
+  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
+  background: var(--df-danger); color: #fff;
+  padding: 10px 18px; border-radius: var(--df-radius-sm);
+  font-size: 13px; z-index: 9999; max-width: 90vw;
+  box-shadow: 0 4px 16px rgba(0,0,0,0.3);
+}
+.toast-enter-active, .toast-leave-active { transition: all 0.25s var(--df-ease); }
+.toast-enter-from, .toast-leave-to { opacity: 0; transform: translate(-50%, 10px); }
 </style>