feat: 实现运营商模块重构，添加冗余字段优化查询性能

主要变更：
- 新增 Carrier CRUD API（创建、列表、详情、更新、删除、状态更新）
- IotCard/IotCardImportTask 添加 carrier_type/carrier_name 冗余字段
- 移除 Carrier 表的 channel_name/channel_code 字段
- 查询时直接使用冗余字段，避免 JOIN Carrier 表
- 添加数据库迁移脚本（000021-000023）
- 添加单元测试和集成测试
- 同步更新 OpenAPI 文档和 specs

migrations/000021_carrier_remove_channel_fields.down.sql

@@ -0,0 +1,12 @@
+-- 回滚：恢复 Carrier 表的 channel_name、channel_code 字段
+
+-- 添加 channel_name 字段
+ALTER TABLE tb_carrier ADD COLUMN channel_name VARCHAR(100);
+COMMENT ON COLUMN tb_carrier.channel_name IS '渠道名称';
+
+-- 添加 channel_code 字段
+ALTER TABLE tb_carrier ADD COLUMN channel_code VARCHAR(50);
+COMMENT ON COLUMN tb_carrier.channel_code IS '渠道编码';
+
+-- 重建联合唯一索引（carrier_type + channel_code，排除已删除记录）
+CREATE UNIQUE INDEX idx_carrier_type_channel ON tb_carrier(carrier_type, channel_code) WHERE deleted_at IS NULL;

migrations/000021_carrier_remove_channel_fields.up.sql

@@ -0,0 +1,11 @@
+-- 移除 Carrier 表的 channel_name、channel_code 字段及相关索引
+-- 这些字段未被任何地方使用，属于冗余设计
+
+-- 先删除联合唯一索引
+DROP INDEX IF EXISTS idx_carrier_type_channel;
+
+-- 删除 channel_name 字段
+ALTER TABLE tb_carrier DROP COLUMN IF EXISTS channel_name;
+
+-- 删除 channel_code 字段
+ALTER TABLE tb_carrier DROP COLUMN IF EXISTS channel_code;

migrations/000022_iot_card_add_carrier_redundant_fields.down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE tb_iot_card DROP COLUMN IF EXISTS carrier_type;
+ALTER TABLE tb_iot_card DROP COLUMN IF EXISTS carrier_name;

migrations/000022_iot_card_add_carrier_redundant_fields.up.sql

@@ -0,0 +1,14 @@
+-- IotCard 表添加 carrier_type、carrier_name 冗余字段
+-- 导入时从 Carrier 表快照，后续查询无需 JOIN
+
+ALTER TABLE tb_iot_card ADD COLUMN carrier_type VARCHAR(20);
+ALTER TABLE tb_iot_card ADD COLUMN carrier_name VARCHAR(100);
+
+COMMENT ON COLUMN tb_iot_card.carrier_type IS '运营商类型(CMCC/CUCC/CTCC/CBN)，导入时快照';
+COMMENT ON COLUMN tb_iot_card.carrier_name IS '运营商名称，导入时快照';
+
+-- 从 Carrier 表填充现有数据
+UPDATE tb_iot_card 
+SET carrier_type = c.carrier_type, carrier_name = c.carrier_name
+FROM tb_carrier c 
+WHERE tb_iot_card.carrier_id = c.id;

migrations/000023_import_task_add_carrier_name.down.sql

@@ -0,0 +1 @@
+ALTER TABLE tb_iot_card_import_task DROP COLUMN IF EXISTS carrier_name;

migrations/000023_import_task_add_carrier_name.up.sql

@@ -0,0 +1,11 @@
+-- IotCardImportTask 表添加 carrier_name 冗余字段（已有 carrier_type）
+
+ALTER TABLE tb_iot_card_import_task ADD COLUMN carrier_name VARCHAR(100);
+
+COMMENT ON COLUMN tb_iot_card_import_task.carrier_name IS '运营商名称，创建任务时快照';
+
+-- 从 Carrier 表填充现有数据
+UPDATE tb_iot_card_import_task 
+SET carrier_name = c.carrier_name
+FROM tb_carrier c 
+WHERE tb_iot_card_import_task.carrier_id = c.id;