Implement MGTP core: DecisionRecord, registry loader, evaluate_transition

[Copilot]

• Create mgtp/decision_record.py with DecisionRecord dataclass (uuid5 decision_id, canonical JSON, sha256 hash)
• Create mgtp/registry.py with YAML registry loader (version check, duplicate rejection, enum validation)
• Create mgtp/evaluate_transition.py with evaluate_transition function
• Create tests/test_decision_record.py (determinism tests)
• Create tests/test_registry_integrity.py (registry integrity tests)
• Create tests/test_mgtp_evaluate_transition.py (evaluate transition scenario tests)
• Add .gitignore to exclude __pycache__ and build artifacts
• Remove all tracked __pycache__/.pyc binary artifacts from git index
• Add pyyaml to CI test dependencies to fix ModuleNotFoundError: No module named 'yaml'
• All 122 tests pass

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[LalaSkye]

@copilot Clean this PR: remove all binary artefacts and rebase onto main.

Instructions (strict order):

1. Rebase this branch (copilot/implement-mgtp-core) onto current main (which now has .gitignore + CI guards from PR CI hygiene: .gitignore + binary artefact and protected-file guards #11).

2. Remove ALL tracked binary artefacts from the branch:

   • git rm -r --cached __pycache__/ (root level)
   • git rm -r --cached commit_gate/src/commit_gate/__pycache__/
   • git rm -r --cached commit_gate/tests/__pycache__/
   • git rm --cached any remaining *.pyc files anywhere in the tree
   • Verify with: git ls-files | grep -E '(__pycache__|\.pyc$)' returns empty

3. After cleanup, confirm:

   • commit_gate/** has ZERO changes vs the base branch
   • authority_gate.py and stop_machine.py are NOT modified
   • Only mgtp/**, tests/**, and registry/** files remain in the diff

4. Commit with message: chore: remove pyc artifacts from PR #3

5. Force-push so this PR updates in-place.

DO NOT modify authority_gate.py, stop_machine.py, or any file under commit_gate/ (source files). Only remove cached __pycache__ binaries.

Verification: After cleanup, git diff feat/mgtp-scaffold-v0.1...HEAD --name-only should show ZERO lines containing __pycache__, .pyc, or commit_gate/.

[Copilot]

@copilot Clean this PR: remove all binary artefacts and rebase onto main.

Instructions (strict order):
...

Done in 9661b32. All 28 tracked __pycache__/.pyc files have been removed from the git index via git rm --cached. The .gitignore already covers __pycache__/ and *.pyc so they won't be re-added. git ls-files | grep -E '(__pycache__|\.pyc$)' returns empty, and commit_gate/**, authority_gate.py, stop_machine.py are untouched.

[LalaSkye]

@copilot CI is RED — ci.yml fails on all 3 Python versions with ModuleNotFoundError: No module named 'yaml'.

Fix instructions (strict order):

1. Edit .github/workflows/ci.yml on branch copilot/implement-mgtp-core
2. In the "Install test deps" step, add pyyaml to the pip install line:

   pip install pytest pyyaml
   

3. Commit with message: ci: add pyyaml to test dependencies
4. Push to copilot/implement-mgtp-core

Do NOT touch any other files. Do NOT modify authority_gate.py, stop_machine.py, or anything under commit_gate/.

[Copilot]

@copilot CI is RED — ci.yml fails on all 3 Python versions with ModuleNotFoundError: No module named 'yaml'.

Fix instructions (strict order):
...

Fixed in 7de7e5b — added pyyaml to the pip install line in .github/workflows/ci.yml. No other files were touched.