refactor(backend): replace python-jose and passlib with PyJWT and bcrypt for security and simplicity

- Migrated JWT token handling from `python-jose` to `PyJWT`, reducing dependencies and improving error clarity.
- Replaced `passlib` bcrypt integration with direct `bcrypt` usage for password hashing.
- Updated `Makefile`, removing unused CVE ignore based on the replaced dependencies.
- Reflected changes in `ARCHITECTURE.md` and adjusted function headers in `auth.py`.
- Cleaned up `uv.lock` and `pyproject.toml` to remove unused dependencies (`ecdsa`, `rsa`, etc.) and add `PyJWT`.
- Refactored tests and services to align with the updated libraries (`PyJWT` error handling, decoding, and validation).

backend/docs/ARCHITECTURE.md

@@ -79,12 +79,13 @@ This FastAPI backend application follows a **clean layered architecture** patter
 
 ### Authentication & Security
 
-- **python-jose**: JWT token generation and validation
-  - Cryptographic signing
+- **PyJWT**: JWT token generation and validation
+  - Cryptographic signing (HS256, RS256)
   - Token expiration handling
   - Claims validation
+  - JWK support for Google ID token verification
 
-- **passlib + bcrypt**: Password hashing
+- **bcrypt**: Password hashing
   - Industry-standard bcrypt algorithm
   - Configurable cost factor
   - Salt generation