Switch to Pyrefly for type checking instead of mypy

[mhucka]

Is your feature request related to a use case or problem?

A number of other projects are switching from mypy to Pyrefly for type checking Python code. We should do the same for Quantumlib projects if possible. Pyrefly is much faster than mypy and has better IDE support.

What solution or approach do you envision?

1. Use Pyrefly's facility for creating a configuration based on an existing mypy configuration
2. Run Pyrefly to find and fix whatever problems it flags
3. Add a Pyrefly hook configuration to .pre-commit-config.yaml
4. Replace the type check in CI with a Pyrefly-based one

How urgent is this for you?

P2 – needed within two quarters