chore(deps): 升级 TanStack Start 至 1.167.48，移除 start-plugin-core patch

upstream 已修（PR #7249，1.169.4 拆分 vite/rsbuild subpath，
@rsbuild/core 列为 optional peer），patches/ 不再必要。

- @tanstack/react-start ^1.167.43 → ^1.167.48
- @tanstack/react-router ^1.168.23 → ^1.168.24
  (react-start@1.167.48 exact 依赖，避免 lockfile 双版本)
- 删除 patches/@tanstack%2Fstart-plugin-core@1.168.0.patch
- 删除 package.json patchedDependencies 块
- AGENTS.md 移除 patches/ layout 说明

验证：fix / typecheck / test / build / compile 均通过；
start-plugin-core@1.169.4 dist 不再静态 import rsbuild。

package.json

@@ -34,9 +34,9 @@
     "@orpc/zod": "^1.14.0",
     "@t3-oss/env-core": "^0.13.11",
     "@tanstack/react-query": "^5.100.1",
-    "@tanstack/react-router": "^1.168.23",
+    "@tanstack/react-router": "^1.168.24",
     "@tanstack/react-router-ssr-query": "^1.166.11",
-    "@tanstack/react-start": "^1.167.43",
+    "@tanstack/react-start": "^1.167.48",
     "citty": "^0.2.2",
     "drizzle-orm": "0.45.2",
     "drizzle-zod": "^0.8.3",
@@ -60,8 +60,5 @@
     "tailwindcss": "^4.2.4",
     "typescript": "^6.0.3",
     "vite": "^8.0.10"
-  },
-  "patchedDependencies": {
-    "@tanstack/start-plugin-core@1.168.0": "patches/@tanstack%2Fstart-plugin-core@1.168.0.patch"
   }
 }