Add comprehensive input validation middleware for controller layer

[grantfox-development]

Problem

Controllers and services lack consistent input validation. While the Photo module (src/modules/photo/presentation/controllers/PhotoController.ts) uses express-validator, most endpoints accept raw request bodies without validation, including:

• createVolunteer in src/controllers/VolunteerController.ts
• createProject in src/controllers/Project.controller.ts
• Auth endpoints (register/login)

This creates risk of:

• Invalid data types persisting to the database (e.g., parseInt(userId, 10) in PhotoController.ts:51 without prior validation).
• Missing required fields not caught until the service/repository layer.
• Date parsing issues (new Date(startDate) in the project controller without format validation).
• Inconsistent error responses for validation failures across modules.

express-validator and class-validator are already installed but underutilized.

Proposed Solution

1. Create a reusable ValidationPipe middleware in src/middleware/ that wraps express-validator chains and returns a standardized 400 response.
2. Define DTOs/validation schemas using class-validator decorators in src/dtos/ (or co-located with each module): CreateProjectDTO, CreateVolunteerDTO, RegisterUserDTO, LoginDTO, UploadPhotoDTO.
3. Apply the validation middleware consistently across auth, project, volunteer, user, and photo routes.
4. Standardize the validation error response format with field-level error details.
5. Add tests/validation.test.ts covering positive and negative cases for at least 5 critical endpoints.

Acceptance Criteria

• Validation middleware handles email, UUID, date, enum, and custom string-length/regex constraints.
• All POST/PUT endpoints have validation applied; invalid input returns HTTP 400 with structured field-level errors.
• DTOs document the expected input schema and live next to the module they serve.
• At least 5 critical endpoints covered: register, login, createProject, createVolunteer, upload photo.
• Integration test validates both passing and failing validation paths and checks error response shape.
• No regression in existing tests; CI passes.

Out of Scope

• Refactoring existing service-layer validation (separate effort).
• Changing the auth strategy or JWT logic.

Suggested Labels

enhancement, code-quality, testing