feat(auth): enhance session management and improve user flow

- Add type annotations for H3Event and EventHandlerRequest
- Refactor session generation to include user info in cookies
- Improve password validation for non-development environments
- Simplify session setting in login and register handlers
- Adjust routing logic after login and registration
- Remove redundant router pushes in auth store functions
- Update auth middleware to use session token for validation
- Display error messages on login and registration failures