feat(auth): implement user registration and login with JWT authentication

- Added `bcrypt`, `jsonwebtoken`, and `once_cell` dependencies to manage password hashing and JWT handling.
- Created `Claims` struct for JWT claims and implemented token generation in the login route.
- Implemented user registration and authentication logic in the `auth` module.
- Updated error handling to include validation errors.
- Created new routes for user registration and login, and integrated them into the main router.
- Added tests for the authentication flow, including registration and login scenarios.
- Updated user model to include a password hash field.
- Refactored user creation logic to include password validation.
- Adjusted feed and user routes to utilize JWT for authentication.

thoughts-backend/app/Cargo.toml

@@ -9,6 +9,8 @@ name = "app"
 path = "src/lib.rs"
 
 [dependencies]
+bcrypt = "0.17.1"
 models = { path = "../models" }
+validator = "0.20"
 
 sea-orm = { workspace = true }