fix(skill_utils): add type check for metadata field in extract_skill_conditions

When PyYAML is unavailable or YAML frontmatter is malformed, the fallback
parser may return metadata as a string instead of a dict. This causes
AttributeError when calling .get("hermes") on the string.

Added explicit type checks to handle cases where metadata or hermes fields
are not dicts, preventing the crash.

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

agent/skill_utils.py

@@ -230,7 +230,13 @@ def get_all_skills_dirs() -> List[Path]:
 
 def extract_skill_conditions(frontmatter: Dict[str, Any]) -> Dict[str, List]:
     """Extract conditional activation fields from parsed frontmatter."""
-    hermes = (frontmatter.get("metadata") or {}).get("hermes") or {}
+    metadata = frontmatter.get("metadata")
+    # Handle cases where metadata is not a dict (e.g., a string from malformed YAML)
+    if not isinstance(metadata, dict):
+        metadata = {}
+    hermes = metadata.get("hermes") or {}
+    if not isinstance(hermes, dict):
+        hermes = {}
     return {
         "fallback_for_toolsets": hermes.get("fallback_for_toolsets", []),
         "requires_toolsets": hermes.get("requires_toolsets", []),