重构: 前端DRY(style全局沉淀 + ts/js公共沉淀)

style-dry:
- 新增 src/styles/components.css: .info-item*/.panel/.panel-header/.tech-tag/.card-tags 全局
- main.ts 注册 import
- 删重复: ProjectDetail/TaskDetail/TaskOutputCard/ProjectCard/Projects(scoped删重复, 全局对子组件生效)
- 未使用清理: Projects .card-progress dead(1处保守核对)

tsjs-dry:
- aiShared.ts: resolveAiLang(合并useAiSend.resolveLang + useAiContext.resolveLanguage)
- stores/knowledge.ts: kindText/kindLabel/kindIcon/knowledgeStatusLabel/knowledgeConfidenceLabel(5公共)
- 删重复: useAiSend/useAiContext(resolveLang) + Knowledge/KnowledgeDetail(4+5 helper) + ActiveProjectsPanel(formatLastActivity→formatRelativeZh复用)

strategy: DRY收口, 公共沉淀(utils/store/shared); relativeTime非纯重复保留; .btn/.empty-hint局部override WATCH未动

src/main.ts

@@ -4,6 +4,7 @@ import router from "./router";
 import i18n from "./i18n";
 import "./styles/global.css";
 import "./styles/ai-md.css";
+import "./styles/components.css";
 
 const app = createApp(App);