日K加载提速：adj_factor 覆盖索引 + 冷路径并发 + 热路径进程内缓存直返

- adj_factor 覆盖索引 (ts_code,trade_date) INCLUDE (adj_factor)：根治堆碎片化
  （单股 6516 行散 6516 块，满载时位图堆扫 1.5s+），Index Only Scan ~2ms；
  因子查询全部改 2 列投影，lag() 窗口只取变点（6516→32 行）
- preview 冷路径 2 会话 2 波并发，信息卡合并为 LEFT JOIN LATERAL 一条
- 鉴权会话 60s 进程内缓存（登出/全端登出即时失效），全站请求省 ~80ms
- pvj/chipsj/stocksj/facetsj 存 model_dump_json 原串直返（与 response_model
  字节一致），热路径 230-2190ms → 1-2ms；get_version 本地缓存+bump 即时可见
- 连接池 10+20；smoke_test 适配鉴权缓存

frontend_dev.log

@@ -1,9 +1,17 @@
 $ vite
 
-  VITE v6.4.3  ready in 598 ms
+  VITE v6.4.3  ready in 2144 ms
 
   ➜  Local:   http://localhost:5173/
   ➜  Network: use --host to expose
-00:44:18 [vite] (client) hmr update /src/style.css, /@fs/D:\Project\stock\frontend\src\components\DetailKLine.vue
-00:44:23 [vite] (client) hmr update /@fs/D:\Project\stock\frontend\src\components\DetailKLine.vue, /src/style.css
-00:44:24 [vite] (client) hmr update /src/style.css, /@fs/D:\Project\stock\frontend\src\components\DetailKLine.vue
+15:58:04 [vite] http proxy error: /api/auth/me
+AggregateError [ECONNREFUSED]: 
+    at internalConnectMultiple (node:net:1134:18)
+    at afterConnectMultiple (node:net:1715:7)
+$ vite
+Port 5173 is in use, trying another one...
+
+  VITE v6.4.3  ready in 579 ms
+
+  ➜  Local:   http://localhost:5174/
+  ➜  Network: use --host to expose