fix(db): align migrations with entity model and idempotency

backend/mci-server/src/main/resources/db/migration/V1__init_account.sql

@@ -16,7 +16,8 @@ CREATE TABLE IF NOT EXISTS mci_platform_role (
     role_name VARCHAR(128) NOT NULL COMMENT '角色名称',
     permissions JSON COMMENT '权限列表',
     status TINYINT NOT NULL DEFAULT 1,
-    create_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
+    create_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    update_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='平台角色表';
 
 CREATE TABLE IF NOT EXISTS mci_user (
@@ -41,3 +42,7 @@ CREATE TABLE IF NOT EXISTS mci_user_role (
     create_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
     UNIQUE KEY uk_user_role (user_id, role_id)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='用户角色关系表';
+
+ALTER TABLE mci_user_role
+    ADD CONSTRAINT fk_user_role_user_id FOREIGN KEY (user_id) REFERENCES mci_user (id),
+    ADD CONSTRAINT fk_user_role_role_id FOREIGN KEY (role_id) REFERENCES mci_platform_role (id);

backend/mci-server/src/main/resources/db/migration/V2__seed_roles.sql

@@ -1,4 +1,4 @@
-INSERT INTO mci_platform_role (role_code, role_name, permissions) VALUES
+INSERT IGNORE INTO mci_platform_role (role_code, role_name, permissions) VALUES
 ('admin', '租户管理员', '["*"]'),
 ('operator', '运营操作员', '["send:write", "channel:read", "channel:write", "record:read"]'),
 ('viewer', '只读用户', '["record:read", "channel:read"]');