fix(template): 修复模板库保存/颜色/拖拽排序，联动OntologyInspector，种子腹腔镜35分类模板

- backend/schemas.py: TemplateUpdate 添加 classes/rules 字段
- backend/models.py: Template 添加 description 列
- backend/routers/templates.py: create/update 打包/解包 mapping_rules.classes (已有)
- backend/main.py: seed 腹腔镜胆囊切除术35分类模板
- src/lib/api.ts: updateTemplate 改 PATCH，补齐 color/z_index，_mapTemplate 对齐 TS 接口
- src/store/useStore.ts: 新增 activeTemplateId/setActiveTemplateId
- src/components/TemplateRegistry.tsx: 随机颜色(HSL轮盘)、HTML5拖拽排序、批量JSON导入、一键载入腹腔镜模板、handleSave 补齐必填字段
- src/components/OntologyInspector.tsx: 完全重写，从store读取模板，支持模板切换和自定义分类
- src/components/VideoWorkspace.tsx: 进入时自动加载模板列表
- src/components/ProjectLibrary.tsx: 修复状态字符串 TS 严格类型报错
- 工程分析/: 更新实现方案与经验记录

Timestamp: 20260430_222830

src/components/VideoWorkspace.tsx

@@ -1,6 +1,6 @@
 import React, { useEffect } from 'react';
 import { useStore } from '../store/useStore';
-import { getProjectFrames, parseMedia } from '../lib/api';
+import { getProjectFrames, parseMedia, getTemplates } from '../lib/api';
 import { CanvasArea } from './CanvasArea';
 import { ToolsPalette } from './ToolsPalette';
 import { OntologyInspector } from './OntologyInspector';
@@ -63,6 +63,15 @@ export function VideoWorkspace({ onNavigateToAI }: { onNavigateToAI?: () => void
     return () => { cancelled = true; };
   }, [currentProject?.id, setFrames, setCurrentFrame]);
 
+  const templates = useStore((state) => state.templates);
+  const setTemplates = useStore((state) => state.setTemplates);
+
+  useEffect(() => {
+    if (templates.length === 0) {
+      getTemplates().then((data) => setTemplates(data)).catch(console.error);
+    }
+  }, [templates.length, setTemplates]);
+
   const currentFrameUrl = frames[currentFrameIndex]?.url || '';
 
   return (