feat: 新增 target description 字段，收紧 id/name 长度，调整延迟列和名称列

src/server/checker/runner/db/execute.ts

@@ -180,6 +180,7 @@ export class DbChecker implements CheckerDefinition<ResolvedDbTarget> {
         query: t.db.query,
         url: t.db.url,
       },
+      description: null,
       expect: target.expect as DbExpectConfig | undefined,
       group: target.group ?? "default",
       id: t.id,