feat: 实现 RBAC 权限系统和数据权限控制 (004-rbac-data-permission)

主要功能:
- 实现完整的 RBAC 权限系统（账号、角色、权限的多对多关联）
- 基于 owner_id + shop_id 的自动数据权限过滤
- 使用 PostgreSQL WITH RECURSIVE 查询下级账号
- Redis 缓存优化下级账号查询性能（30分钟过期）
- 支持多租户数据隔离和层级权限管理

技术实现:
- 新增 Account、Role、Permission 模型及关联关系表
- 实现 GORM Scopes 自动应用数据权限过滤
- 添加数据库迁移脚本（000002_rbac_data_permission、000003_add_owner_id_shop_id）
- 完善错误码定义（1010-1027 为 RBAC 相关错误）
- 重构 main.go 采用函数拆分提高可读性

测试覆盖:
- 添加 Account、Role、Permission 的集成测试
- 添加数据权限过滤的单元测试和集成测试
- 添加下级账号查询和缓存的单元测试
- 添加 API 回归测试确保向后兼容

文档更新:
- 更新 README.md 添加 RBAC 功能说明
- 更新 CLAUDE.md 添加技术栈和开发原则
- 添加 docs/004-rbac-data-permission/ 功能总结和使用指南

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/integration/task_test.go

@@ -29,7 +29,7 @@ func TestTaskSubmit(t *testing.T) {
 	redisClient := redis.NewClient(&redis.Options{
 		Addr: "localhost:6379",
 	})
-	defer redisClient.Close()
+	defer func() { _ = redisClient.Close() }()
 
 	// 清理测试数据
 	ctx := context.Background()
@@ -39,7 +39,7 @@ func TestTaskSubmit(t *testing.T) {
 	client := asynq.NewClient(asynq.RedisClientOpt{
 		Addr: "localhost:6379",
 	})
-	defer client.Close()
+	defer func() { _ = client.Close() }()
 
 	// 构造任务载荷
 	payload := &EmailPayload{
@@ -72,7 +72,7 @@ func TestTaskPriority(t *testing.T) {
 	redisClient := redis.NewClient(&redis.Options{
 		Addr: "localhost:6379",
 	})
-	defer redisClient.Close()
+	defer func() { _ = redisClient.Close() }()
 
 	ctx := context.Background()
 	redisClient.FlushDB(ctx)
@@ -81,7 +81,7 @@ func TestTaskPriority(t *testing.T) {
 	client := asynq.NewClient(asynq.RedisClientOpt{
 		Addr: "localhost:6379",
 	})
-	defer client.Close()
+	defer func() { _ = client.Close() }()
 
 	tests := []struct {
 		name  string
@@ -118,7 +118,7 @@ func TestTaskRetry(t *testing.T) {
 	redisClient := redis.NewClient(&redis.Options{
 		Addr: "localhost:6379",
 	})
-	defer redisClient.Close()
+	defer func() { _ = redisClient.Close() }()
 
 	ctx := context.Background()
 	redisClient.FlushDB(ctx)
@@ -126,7 +126,7 @@ func TestTaskRetry(t *testing.T) {
 	client := asynq.NewClient(asynq.RedisClientOpt{
 		Addr: "localhost:6379",
 	})
-	defer client.Close()
+	defer func() { _ = client.Close() }()
 
 	payload := &EmailPayload{
 		RequestID: "retry-test-001",
@@ -155,7 +155,7 @@ func TestTaskIdempotency(t *testing.T) {
 	redisClient := redis.NewClient(&redis.Options{
 		Addr: "localhost:6379",
 	})
-	defer redisClient.Close()
+	defer func() { _ = redisClient.Close() }()
 
 	ctx := context.Background()
 	redisClient.FlushDB(ctx)
@@ -190,7 +190,7 @@ func TestTaskStatusTracking(t *testing.T) {
 	redisClient := redis.NewClient(&redis.Options{
 		Addr: "localhost:6379",
 	})
-	defer redisClient.Close()
+	defer func() { _ = redisClient.Close() }()
 
 	ctx := context.Background()
 	redisClient.FlushDB(ctx)
@@ -222,7 +222,7 @@ func TestQueueInspection(t *testing.T) {
 	redisClient := redis.NewClient(&redis.Options{
 		Addr: "localhost:6379",
 	})
-	defer redisClient.Close()
+	defer func() { _ = redisClient.Close() }()
 
 	ctx := context.Background()
 	redisClient.FlushDB(ctx)
@@ -230,7 +230,7 @@ func TestQueueInspection(t *testing.T) {
 	client := asynq.NewClient(asynq.RedisClientOpt{
 		Addr: "localhost:6379",
 	})
-	defer client.Close()
+	defer func() { _ = client.Close() }()
 
 	// 提交多个任务
 	for i := 0; i < 5; i++ {
@@ -253,7 +253,7 @@ func TestQueueInspection(t *testing.T) {
 	inspector := asynq.NewInspector(asynq.RedisClientOpt{
 		Addr: "localhost:6379",
 	})
-	defer inspector.Close()
+	defer func() { _ = inspector.Close() }()
 
 	// 获取队列信息
 	info, err := inspector.GetQueueInfo(constants.QueueDefault)