fix: 省份图表"未知"合入"其他"

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/server/routes/vehicles.ts

@@ -1060,9 +1060,10 @@ app.get('/region-chart', async (c) => {
     }
   }
 
-  // 分离"其他"，对非"其他"排序取 Top N，剩余全部合入"其他"
-  const otherCount = counts.get('其他') || 0;
+  // 分离"其他"和"未知"，对剩余排序取 Top N，其余全部合入"其他"
+  const otherCount = (counts.get('其他') || 0) + (counts.get('未知') || 0);
   counts.delete('其他');
+  counts.delete('未知');
 
   const sorted = Array.from(counts.entries())
     .map(([name, value]) => ({ name, value }))