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/api/Cargo.toml

@@ -14,6 +14,9 @@ serde = { workspace = true }
 tower = { workspace = true }
 tracing = { workspace = true }
 validator = { workspace = true, features = ["derive"] }
+bcrypt = "0.17.1"
+jsonwebtoken = "9.3.1"
+once_cell = "1.21.3"
 
 tower-http = { version = "0.6.6", features = ["fs", "cors"] }
 tower-cookies = "0.11.0"