feat(mindmodel): add manifest loader and tests

scripts/mindmodel/loader.py

@@ -0,0 +1,67 @@
+"""Simple manifest loader for mindmodel manifests.
+
+Provides `load_manifest(path: str) -> dict` and `ManifestLoadError`.
+
+Behavior:
+- If PyYAML is installed, uses yaml.safe_load to parse the file.
+- Otherwise falls back to the stdlib json parser.
+- If the top-level document is a list it will be normalized to {"constraints": <list>}.
+- Raises ManifestLoadError for missing file or parse errors.
+"""
+
+from typing import Any, Dict
+import json
+from pathlib import Path
+
+
+class ManifestLoadError(Exception):
+    """Raised when a manifest cannot be loaded or parsed."""
+
+
+try:
+    import yaml  # type: ignore
+except Exception:  # YAML not available
+    yaml = None  # type: ignore
+
+
+def _parse_with_yaml(text: str) -> Any:
+    # yamlsafe_load may return any Python structure
+    try:
+        return yaml.safe_load(text)
+    except Exception as exc:  # pragma: no cover - defensive
+        raise ManifestLoadError(f"YAML parse error: {exc}") from exc
+
+
+def _parse_with_json(text: str) -> Any:
+    try:
+        return json.loads(text)
+    except Exception as exc:
+        raise ManifestLoadError(f"JSON parse error: {exc}") from exc
+
+
+def load_manifest(path: str) -> Dict[str, Any]:
+    """Load a manifest from the given file path and normalize it to a dict.
+
+    If the top-level document is a list, it will be returned as {"constraints": list}.
+    Raises ManifestLoadError if the file does not exist or if parsing fails.
+    """
+    p = Path(path)
+    if not p.exists():
+        raise ManifestLoadError(f"Manifest file not found: {path}")
+
+    text = p.read_text(encoding="utf-8")
+
+    if yaml is not None:
+        data = _parse_with_yaml(text)
+    else:
+        data = _parse_with_json(text)
+
+    # Normalize
+    if isinstance(data, list):
+        return {"constraints": data}
+
+    if isinstance(data, dict):
+        return data
+
+    # Unexpected top-level type, wrap it
+    return {"manifest": data}