Add Flask web UI, Docker Compose, core engine + tests

- physcom core: CLI, 5-pass pipeline, SQLite repo, 37 tests
- physcom_web: Flask app with HTMX for entity/domain/pipeline/results CRUD
- Docker Compose: web + cli services sharing a named volume for the DB
- Clean up local settings to use wildcard permissions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_combinator.py

@@ -0,0 +1,26 @@
+"""Tests for the Cartesian product combinator."""
+
+import pytest
+
+from physcom.engine.combinator import generate_combinations
+from physcom.models.entity import Entity
+
+
+def test_generates_cartesian_product(seeded_repo):
+    combos = generate_combinations(seeded_repo, ["platform", "power_source"])
+    # 9 platforms x 9 power sources = 81
+    assert len(combos) == 81
+
+
+def test_each_combo_has_one_per_dimension(seeded_repo):
+    combos = generate_combinations(seeded_repo, ["platform", "power_source"])
+    for combo in combos:
+        dims = [e.dimension for e in combo.entities]
+        assert "platform" in dims
+        assert "power_source" in dims
+        assert len(combo.entities) == 2
+
+
+def test_missing_dimension_raises(seeded_repo):
+    with pytest.raises(ValueError, match="No entities found"):
+        generate_combinations(seeded_repo, ["platform", "nonexistent"])