✨ feat(driver-proxy): 新增ClickHouse数据源并提供全局代理独立入口

- 新增 ClickHouse 可选驱动实现与 optional-driver-agent provider，补齐驱动注册与清单配置
- 补齐 ClickHouse 连接与 SQL 适配：连接默认端口/用户、LIMIT、标识符引用、只读编辑限制
- 新增全局代理后端能力与前端持久化配置，更新检查和驱动网络请求统一走代理客户端

frontend/src/utils/sql.ts

@@ -36,7 +36,7 @@ export const quoteIdentPart = (dbType: string, ident: string) => {
   if (!raw) return raw;
   const dbTypeLower = (dbType || '').toLowerCase();
 
-  if (dbTypeLower === 'mysql' || dbTypeLower === 'mariadb' || dbTypeLower === 'diros' || dbTypeLower === 'sphinx' || dbTypeLower === 'tdengine') {
+  if (dbTypeLower === 'mysql' || dbTypeLower === 'mariadb' || dbTypeLower === 'diros' || dbTypeLower === 'sphinx' || dbTypeLower === 'tdengine' || dbTypeLower === 'clickhouse') {
     return `\`${raw.replace(/`/g, '``')}\``;
   }