feat: sites表支持多名称/多地址(names/urls JSON列), DTO/Service/前端全部适配

par-core/src/main/resources/db/migration/V6__site_multi_names_urls.sql

@@ -0,0 +1,9 @@
+-- 支持多站点名称和多地址
+ALTER TABLE sites
+    ADD COLUMN names TEXT COMMENT '站点名称列表（JSON数组）' AFTER name,
+    ADD COLUMN urls  TEXT COMMENT '站点地址列表（JSON数组）' AFTER base_url,
+    ADD COLUMN notes TEXT COMMENT '备注/其他信息' AFTER description;
+
+-- 迁移现有单值数据到JSON数组
+UPDATE sites SET names = JSON_ARRAY(name) WHERE name IS NOT NULL AND name != '';
+UPDATE sites SET urls = JSON_ARRAY(base_url) WHERE base_url IS NOT NULL AND base_url != '';