feat(mindmodel): add manifest loader and tests

tests/scripts/mindmodel/test_loader.py

@@ -0,0 +1,21 @@
+import json
+import pytest
+
+from scripts.mindmodel import loader
+
+
+def test_load_json_manifest(tmp_path):
+    data = [{"id": "c1", "description": "a constraint"}]
+    p = tmp_path / "manifest.json"
+    p.write_text(json.dumps(data), encoding="utf-8")
+
+    loaded = loader.load_manifest(str(p))
+
+    assert isinstance(loaded, dict)
+    assert "constraints" in loaded
+    assert any(c.get("id") == "c1" for c in loaded["constraints"])
+
+
+def test_missing_manifest_raises():
+    with pytest.raises(loader.ManifestLoadError):
+        loader.load_manifest("nonexistent-file-manifest.json")