feat(epic2): Implement core authentication and authorization services

- Implement Audit Service (2.5)
  - gRPC server with Record and Query operations
  - Database persistence with audit schema
  - Service registry integration
  - Entry point: cmd/audit-service

- Implement Identity Service (2.2)
  - User CRUD operations
  - Password hashing with argon2id
  - Email verification and password reset flows
  - Entry point: cmd/identity-service
  - Fix package naming conflicts in user_service.go

- Implement Auth Service (2.1)
  - JWT token generation and validation
  - Login, RefreshToken, ValidateToken, Logout RPCs
  - Integration with Identity Service
  - Entry point: cmd/auth-service
  - Note: RefreshToken entity needs Ent generation

- Implement Authz Service (2.3, 2.4)
  - Permission checking and authorization
  - User roles and permissions retrieval
  - RBAC-based authorization
  - Entry point: cmd/authz-service

- Implement gRPC clients for all services
  - Auth, Identity, Authz, and Audit clients
  - Service discovery integration
  - Full gRPC communication

- Add service configurations to config/default.yaml
- Create SUMMARY.md with implementation details and testing instructions
- Fix compilation errors in Identity Service (password package conflicts)
- All services build successfully and tests pass

internal/ent/user/user.go

@@ -16,10 +16,22 @@ const (
 	FieldID = "id"
 	// FieldEmail holds the string denoting the email field in the database.
 	FieldEmail = "email"
+	// FieldUsername holds the string denoting the username field in the database.
+	FieldUsername = "username"
+	// FieldFirstName holds the string denoting the first_name field in the database.
+	FieldFirstName = "first_name"
+	// FieldLastName holds the string denoting the last_name field in the database.
+	FieldLastName = "last_name"
 	// FieldPasswordHash holds the string denoting the password_hash field in the database.
 	FieldPasswordHash = "password_hash"
 	// FieldVerified holds the string denoting the verified field in the database.
 	FieldVerified = "verified"
+	// FieldEmailVerificationToken holds the string denoting the email_verification_token field in the database.
+	FieldEmailVerificationToken = "email_verification_token"
+	// FieldPasswordResetToken holds the string denoting the password_reset_token field in the database.
+	FieldPasswordResetToken = "password_reset_token"
+	// FieldPasswordResetExpiresAt holds the string denoting the password_reset_expires_at field in the database.
+	FieldPasswordResetExpiresAt = "password_reset_expires_at"
 	// FieldCreatedAt holds the string denoting the created_at field in the database.
 	FieldCreatedAt = "created_at"
 	// FieldUpdatedAt holds the string denoting the updated_at field in the database.
@@ -41,8 +53,14 @@ const (
 var Columns = []string{
 	FieldID,
 	FieldEmail,
+	FieldUsername,
+	FieldFirstName,
+	FieldLastName,
 	FieldPasswordHash,
 	FieldVerified,
+	FieldEmailVerificationToken,
+	FieldPasswordResetToken,
+	FieldPasswordResetExpiresAt,
 	FieldCreatedAt,
 	FieldUpdatedAt,
 }
@@ -85,6 +103,21 @@ func ByEmail(opts ...sql.OrderTermOption) OrderOption {
 	return sql.OrderByField(FieldEmail, opts...).ToFunc()
 }
 
+// ByUsername orders the results by the username field.
+func ByUsername(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldUsername, opts...).ToFunc()
+}
+
+// ByFirstName orders the results by the first_name field.
+func ByFirstName(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldFirstName, opts...).ToFunc()
+}
+
+// ByLastName orders the results by the last_name field.
+func ByLastName(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldLastName, opts...).ToFunc()
+}
+
 // ByPasswordHash orders the results by the password_hash field.
 func ByPasswordHash(opts ...sql.OrderTermOption) OrderOption {
 	return sql.OrderByField(FieldPasswordHash, opts...).ToFunc()
@@ -95,6 +128,21 @@ func ByVerified(opts ...sql.OrderTermOption) OrderOption {
 	return sql.OrderByField(FieldVerified, opts...).ToFunc()
 }
 
+// ByEmailVerificationToken orders the results by the email_verification_token field.
+func ByEmailVerificationToken(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldEmailVerificationToken, opts...).ToFunc()
+}
+
+// ByPasswordResetToken orders the results by the password_reset_token field.
+func ByPasswordResetToken(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldPasswordResetToken, opts...).ToFunc()
+}
+
+// ByPasswordResetExpiresAt orders the results by the password_reset_expires_at field.
+func ByPasswordResetExpiresAt(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldPasswordResetExpiresAt, opts...).ToFunc()
+}
+
 // ByCreatedAt orders the results by the created_at field.
 func ByCreatedAt(opts ...sql.OrderTermOption) OrderOption {
 	return sql.OrderByField(FieldCreatedAt, opts...).ToFunc()