Configure Pyrefly tooling

[yash2006kr]

Addresses #174.

Summary

• add the Google OSS Pyrefly configuration for smart_control
• add Pyrefly to the Poetry dev dependency group and regenerate poetry.lock
• run Pyrefly from GitHub Actions and pre-commit hooks in report-only mode
• document the new type-checking workflow for contributors

Notes

Pyrefly currently reports existing findings in the repository, so this PR wires the check in as non-blocking for now. This matches the discussion in #174/#175 about landing the tooling before the upcoming internal sync-out resolves the current findings. The TODO comments mark the CI and pre-commit places where || true / report-only behavior can be removed later.

Validation

• poetry lock
• poetry check (passes with existing Poetry deprecation warnings)
• pyrefly check --config pyrefly.toml (command/config verified; reports existing findings)

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