Stand up the Engine/PIP surface for MAT-WP-0001

Declare layer.yaml, add a Python engine over a local SQLite store,
and cover deterministic assessment, the §13 gap register, stance-map
inventory, claim guardrails, and the gate-house review path with tests.

Assistant: grok
Assistant-Session: 01a04ceb-150e-7e80-a542-ec8b1372e164

Makefile

@@ -0,0 +1,15 @@
+PYTHON ?= python3
+
+.PHONY: install-dev test lint check-layer
+
+install-dev:
+	$(PYTHON) -m pip install -e ".[dev]"
+
+test:
+	PYTHONPATH=src $(PYTHON) -m pytest -q
+
+lint:
+	$(PYTHON) -m ruff check src tests scripts
+
+check-layer:
+	$(PYTHON) scripts/check_layer_conformance.py --report