feat(video-analysis): 完成视频分析模块迭代任务

Bug 修复:
- T-019: 修复品牌API响应解析，正确解析 data[0].brand_name
- T-020: 添加品牌API Bearer Token认证

视频分析功能:
- T-021: SessionID池服务，从内部API获取Cookie列表
- T-022: SessionID自动重试，失效时自动切换重试
- T-023: 巨量云图API封装，支持超时和错误处理
- T-024: 视频分析数据接口 GET /api/v1/videos/{item_id}/analysis
- T-025: 数据库A3指标更新
- T-026: 视频分析前端页面，展示6大类25+指标

测试覆盖率:
- brand_api.py: 100%
- session_pool.py: 100%
- yuntu_api.py: 100%
- video_analysis.py: 99%

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/types/index.ts

@@ -61,3 +61,58 @@ export const QUERY_PLACEHOLDER: Record<QueryType, string> = {
   unique_id: '请输入达人unique_id，每行一个...',
   nickname: '请输入达人昵称关键词...',
 };
+
+// 视频分析数据 (T-026)
+export interface VideoAnalysisData {
+  base_info: {
+    item_id: string;
+    title: string | null;
+    video_url: string | null;
+    star_id: string;
+    star_unique_id: string;
+    star_nickname: string;
+    publish_time: string | null;
+    industry_name: string | null;
+  };
+  reach_metrics: {
+    total_show_cnt: number;
+    natural_show_cnt: number;
+    ad_show_cnt: number;
+    total_play_cnt: number;
+    natural_play_cnt: number;
+    ad_play_cnt: number;
+    effective_play_cnt: number;
+  };
+  a3_metrics: {
+    a3_increase_cnt: number;
+    ad_a3_increase_cnt: number;
+    natural_a3_increase_cnt: number;
+  };
+  search_metrics: {
+    after_view_search_uv: number;
+    after_view_search_pv: number;
+    brand_search_uv: number;
+    product_search_uv: number;
+    return_search_cnt: number;
+  };
+  cost_metrics_raw: {
+    cost: number;
+    natural_cost: number;
+    ad_cost: number;
+  };
+  cost_metrics_calculated: {
+    cpm: number | null;
+    natural_cpm: number | null;
+    cpa3: number | null;
+    natural_cpa3: number | null;
+    cp_search: number | null;
+    estimated_natural_search_uv: number | null;
+    natural_cp_search: number | null;
+  };
+}
+
+export interface VideoAnalysisResponse {
+  success: boolean;
+  data: VideoAnalysisData;
+  error?: string;
+}