Implement JWT authentication and app passkey support

- Add JWT token generation and validation
- Implement bcrypt password hashing
- Create auth service with register/login/refresh/logout
- Add app passkey generation and management
- Implement protected routes and auth middleware
- Add comprehensive tests for new functionality

internal/repository/db.go

@@ -53,5 +53,6 @@ func AutoMigrate(db *gorm.DB) error {
 		&model.User{},
 		&model.Session{},
 		&model.File{},
+		&model.Credential{},
 	)
 }