feat: add jeff verifier tool

[huhaha120]

Summary

• Add a Python verifier under tools/verifier/ with a CLI entry point.
• Validate module structure, value table references, use-before-definition, nested region isolation, instruction input/output signatures, integer bitwidth / float precision consistency, and qubit / qureg linearity.
• Add focused positive and negative tests for the requested verifier checks, plus README usage notes.

Closes #57

Tests

• uv run ruff format --check
• uv run ruff check
• uv run pytest -q
• uv run python -m tools.verifier examples/*/*.jeff

AI Assistance Disclosure

This contribution was AI-assisted. I reviewed the verifier behavior against the issue requirements, checked the CLI and examples manually, and verified the implementation locally with the tests listed above.

[denialhaag]

Thanks for your interest in contributing to jeff in the context of unitaryHACK. Unfortunately, we will have to reject this contribution due to several violations of the unitaryHACK rules. We are happy to review and accept a rules-compliant contribution.