feat(题目列表): SQL 题混在一般题里看不出来，点进去才发现不是写 C——和画流程图一样挂「SQL」标签，「全部类型」里也能单独筛

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/oj/problem/list.vue

@@ -44,7 +44,7 @@ const DIFFICULTIES = [
   { label: "困难", value: "High" },
 ]
 
-const TYPES: ProblemTypeFilter[] = ["reference", "flowchart", "ast"]
+const TYPES: ProblemTypeFilter[] = ["sql", "reference", "flowchart", "ast"]
 
 /** 新生一道还没做对时，顶行引去的知识点 */
 const START_TAG = "输出入门"