fix: 修复调用趋势统计与图表渲染,柱状图改为平滑折线图

- 趋势窗口 off-by-one:窗口不含当天,当天调用永远不进图表;
  改为以 UTC 日界、包含今天的 N 天窗口
- BarChart 容器 items-end 导致列高塌缩,柱子百分比高度恒为 0,
  图表自组件抽取以来从未渲染;重写为 LineChart(单调三次样条
  平滑曲线 + 面积填充 + 十字线 tooltip + 键盘导航)
- nginx 为 index.html 增加 no-cache、/assets/ 增加 immutable
  缓存,避免发版后浏览器沿用旧 bundle

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/web/nginx.conf

@@ -28,7 +28,16 @@ server {
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
 
+    # Hashed build artifacts are safe to cache forever
+    location /assets/ {
+        add_header Cache-Control "public, max-age=31536000, immutable";
+        try_files $uri =404;
+    }
+
     location / {
+        # index.html must always revalidate, or browsers keep a stale
+        # bundle reference after each deploy (heuristic caching)
+        add_header Cache-Control "no-cache";
         try_files $uri $uri/ /index.html;
     }
 }