fix(usage): resolve auto-query interval timing issue

Problem:
- User configured 5-minute auto-query interval
- Actual queries executed every 10 minutes instead of 5

Root Cause:
- staleTime (5 min) conflicted with refetchInterval (5 min)
- React Query skipped refetch when data was still within staleTime
- First interval trigger at T+5min: data considered "fresh", skipped
- Second interval trigger at T+10min: data "stale", executed

Solution:
- Set staleTime to 0 for usage queries
- Ensures refetchInterval executes precisely as configured
- Auto-query is meant to fetch fresh data periodically, not use cache

Technical Details:
- Modified useUsageQuery in src/lib/query/queries.ts
- Changed: staleTime: 5 * 60 * 1000 → staleTime: 0
- Added explanatory comment in Chinese
- Manual queries still work via refetch() button

src/lib/query/queries.ts

@@ -105,7 +105,7 @@ export const useUsageQuery = (
         : false,
     refetchOnWindowFocus: false,
     retry: false,
-    staleTime: 5 * 60 * 1000, // 5分钟
+    staleTime: 0, // 不使用缓存策略，确保 refetchInterval 准确执行
   });
 
   return {