refactor(client): 合并 orpc.ts 和 query-client.ts 为单文件，遵循 ORPC 官方模式

apps/server/AGENTS.md

@@ -54,8 +54,7 @@ bun test -t "pattern"      # Run tests matching pattern
 ```
 src/
 ├── client/                # Client-side code
-│   ├── orpc.ts            # ORPC isomorphic client (internal)
-│   └── query-client.ts    # TanStack Query utils (used by components)
+│   └── orpc.ts            # ORPC client + TanStack Query utils (single entry point)
 ├── components/            # React components
 ├── routes/                # TanStack Router file routes
 │   ├── __root.tsx         # Root layout
@@ -126,7 +125,7 @@ export const router = os.router({ feature })
 ### 4. Use in Components
 ```typescript
 import { useSuspenseQuery, useMutation } from '@tanstack/react-query'
-import { orpc } from '@/client/query-client'
+import { orpc } from '@/client/orpc'
 
 const { data } = useSuspenseQuery(orpc.feature.list.queryOptions())
 const mutation = useMutation(orpc.feature.create.mutationOptions())