Seed repository: rev-8.0.0 reference, frozen oracle, toolchain, test harness

Reference implementation of the strap-beam generators at revision 8.0.0, kept
so the acceptance oracle can be regenerated. Not a live target; the running
application has no OpenSCAD dependency.

The oracle holds 123 frozen cases, 113 accepted and 10 rejected, produced by
OpenSCAD 2021.01 with BOSL2 at 92d697c2. The ten rejections are part of the
contract: a port that accepts them is wrong.

tests/test_oracle.py specifies the port API and was written before the port,
so the interface follows from what must be verified rather than what is
convenient to implement. Proven by adversarial stub: a build() that rejects
everything passes all 10 rejection tests and fails all 226 acceptance tests.

Makefile

@@ -0,0 +1,47 @@
+# Entry points. Every target is safe to run more than once.
+
+PY  ?= venv/bin/python
+PIP ?= venv/bin/pip
+
+.PHONY: help venv deps deps-nocad toolchain verify-oracle regenerate-oracle test test-nocad clean
+
+help:
+	@echo "venv              create the virtualenv (Python 3.11)"
+	@echo "deps              install base + CAD requirements"
+	@echo "deps-nocad        install base requirements only"
+	@echo "toolchain         build the pinned reference toolchain image"
+	@echo "verify-oracle     check the committed oracle is intact"
+	@echo "regenerate-oracle rebuild the oracle inside the pinned image"
+	@echo "test              pytest -n auto"
+	@echo "test-nocad        the separability check: suite must pass without CAD"
+
+venv:
+	test -d venv || python3 -m venv venv
+	$(PIP) install --upgrade pip
+
+deps: venv
+	$(PIP) install -r requirements-base.txt -r requirements-cad.txt
+	$(PIP) install -e .
+
+deps-nocad: venv
+	$(PIP) install -r requirements-base.txt
+	$(PIP) install -e .
+
+toolchain:
+	docker build -t mechcomp/reference-toolchain:8.0.0 tools/reference-toolchain
+
+verify-oracle:
+	python3 fixtures/strap-beam-8.0.0/make_fixtures.py --verify
+
+regenerate-oracle: toolchain
+	./tools/reference-toolchain/verify.sh --full
+
+test:
+	$(PY) -m pytest -n auto
+
+test-nocad:
+	$(PY) -m pytest -n auto -k "not cad"
+
+clean:
+	rm -rf .pytest_cache src/*.egg-info
+	find . -name __pycache__ -type d -prune -exec rm -rf {} +