重构: 前端架构审查降技术债·i18n收口(高ROI)

- 新建 src/i18n/i18n-helpers.ts: 类型安全 t + currentLocale(any中转内部1处带注释)
- 12文件改 i18n as any 样板收口: utils/time + stores(knowledge/project/{ideas,projects,tasks,workflow}) + composables(aiShared/useAiConversations/useAiEvents/useAiSend/useAiStream/useToolCard)
- as any 22→10(i18n 13→0对外), 签名统一(key, named?)
- useToolCard文档块同步(防AI被过时注释误导)

src/composables/ai/useAiConversations.ts

@@ -10,14 +10,11 @@ import { state } from '@/stores/ai'
 import { notifyConversationChanged } from './useAiEvents'
 import { persistUiState } from './useAiPanel'
 import { nextMsgId } from './aiShared'
-import i18n from '@/i18n'
+import { t } from '@/i18n/i18n-helpers'
 import type { AiMessage, AiToolCallInfo } from '@/api/types'
 
 const appSettings = useAppSettingsStore()
 
-// composable 无组件上下文,借全局 i18n 实例翻译错误文案(同 useAiSend/aiShared 模式)
-const t = ((i18n as any).global.t as (k: string, named?: Record<string, unknown>) => string).bind((i18n as any).global)
-
 /** 拉取会话列表;首次加载时若 appSettings 仍有有效 active-conv 且当前无活跃对话则恢复 */
 async function loadConversations() {
   try {