Implement automatic token refresh using stored credentials and TOTP MFA secret. When an API call fails with a 401/unauthorized error, the system now transparently re-authenticates using MONARCH_EMAIL, MONARCH_PASSWORD, and MONARCH_MFA_SECRET, then retries the original request.
Changes:
- Add refresh_authentication() function in auth.py for credential-based login
- Create @retry_on_auth_error decorator to handle and retry failed auth calls
- Apply decorator to all MCP tools (get_accounts, get_transactions, etc.)
- Add MONARCH_MFA_SECRET to .env.example with documentation
- Update login_setup.py to instruct users about required env vars
- Replace PROBLEM.md with PLAN.md documenting the implementation
