🐛 fix(query): 修正新建查询未引用 PostgreSQL 大写表名

- 抽取表查询模板 helper 并统一复用方言标识符引用逻辑
- 修正 Sidebar 与 TableOverview 的表节点新建查询入口
- 补充前端回归测试并更新 issue backlog 记录

Fixes #349

frontend/src/utils/objectQueryTemplates.ts

@@ -0,0 +1,9 @@
+import { quoteQualifiedIdent } from './sql';
+
+export const buildTableSelectQuery = (dbType: string, tableName: string): string => {
+  const normalizedTableName = String(tableName || '').trim();
+  if (!normalizedTableName) {
+    return 'SELECT * FROM ';
+  }
+  return `SELECT * FROM ${quoteQualifiedIdent(dbType, normalizedTableName)};`;
+};