Implement blog API and refactor user data handling

[hussein-m-kandil]

This pull request introduces core blog API features and includes various refactors across the codebase to improve modularity, clarity, and security.

What’s New

• 🧱 Added Prisma models for posts, post comments, and voting behavior.
• ✍️ Implemented CRUD routes for posts and their comments.
• 📄 Added routes to retrieve user posts, comments, and votes.
• 🧼 Refactored users route logic to conform to the new changes.

Enhancements

• 🔒 Globally omitted sensitive fields (e.g., passwords) from user data in API responses.
• 🧩 Extracted and reused filtering logic across different route handlers.
• 🔄 Used a centralized helper to handle all known Prisma DB errors.
• 🔍 Added middleware for optional authentication validation, improving route flexibility.
• 🧪 Refactored integration and manual testing setups for REST API.

Fixes

• 🛠️ Respond with a 404 on a delete user request if it is not found.
• ⚠️ Suppressed irrelevant warnings during DB push in test setup.