feat: add wallet system, donations with auto-rollback, pagination, and API documentation

[Dunsin-cyber]

🔹 PR Description

Overview
This PR introduces core features for the wallet & donation service, including:

• Automatic wallet creation with a default 100,000 balance for every new user
• Ability to send funds to beneficiaries via email lookup
• Safe donations with automatic rollback if any step of the process fails
• Pagination support for all findMany endpoints (users, donations, wallets, etc.)
• Secure authentication using JWT with 15-minute access tokens
• Swagger API documentation for easy testing

Setup & Usage

• Clone the repo, install dependencies with yarn install
• Configure .env with DATABASE_URL, NODE_ENV, JWT_SECRET, etc.
• Start the dev server with yarn dev
• API docs available at http://localhost:[PORT]/api-docs
• Hosted version: https://backend-test-21ij.onrender.com/ (⚠️ free tier, DB expires Sept 13, 2025)

Notes

• Transactions are fully atomic using Prisma $transaction
• Swagger UI supports authentication via the Authorize button
• Documentation updated to reflect new features