fix: preserve dashed-description skill tracking

Use the shared frontmatter parser when verifying surviving extension skill mirrors so delimiter substrings cannot hide provenance metadata.

Assisted-by: GitHub Copilot (model: GPT-5.6 Sol, autonomous)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: marcelsafin

src/specify_cli/extensions/__init__.py

@@ -1657,19 +1657,15 @@ def _extension_owned_skill_names(
                 if not skill_md.is_file():
                     continue
                 try:
-                    import yaml as _yaml
+                    from ..agents import CommandRegistrar as _Registrar
 
                     raw = skill_md.read_text(encoding="utf-8")
-                    source = ""
-                    if raw.startswith("---"):
-                        parts = raw.split("---", 2)
-                        if len(parts) >= 3:
-                            fm = _yaml.safe_load(parts[1]) or {}
-                            source = (
-                                fm.get("metadata", {}).get("source", "")
-                                if isinstance(fm, dict)
-                                else ""
-                            )
+                    fm, _ = _Registrar.parse_frontmatter(raw)
+                    source = (
+                        fm.get("metadata", {}).get("source", "")
+                        if isinstance(fm, dict)
+                        else ""
+                    )
                 except (OSError, UnicodeDecodeError, Exception):
                     continue
                 if source == marker:

tests/test_extension_skills.py

@@ -2364,6 +2364,48 @@ def test_unregister_agent_artifacts_preserves_tracking_for_other_agent_mirror(
             "dropped by the earlier auggie-scoped unregister call (#2948)"
         )
 
+    def test_unregister_agent_artifacts_preserves_dashed_description_mirror_tracking(
+        self, project_dir, temp_dir
+    ):
+        """A ``---`` substring in frontmatter must not hide mirror ownership."""
+        extension_id = "dash-mirror-ext"
+        skill_name = f"speckit-{extension_id}-hello"
+
+        _create_init_options(project_dir, ai="auggie", ai_skills=True)
+        manager = ExtensionManager(project_dir)
+        manager.install_from_directory(
+            _create_dashed_description_extension_dir(
+                temp_dir, ext_id=extension_id
+            ),
+            "0.1.0",
+            register_commands=False,
+        )
+        manager.register_enabled_extensions_for_agent("auggie")
+
+        _create_init_options(project_dir, ai="copilot", ai_skills=True)
+        manager.register_enabled_extensions_for_agent("copilot")
+
+        auggie_skill = (
+            project_dir / ".augment" / "skills" / skill_name / "SKILL.md"
+        )
+        copilot_skill = (
+            project_dir / ".github" / "skills" / skill_name / "SKILL.md"
+        )
+        assert auggie_skill.exists() and copilot_skill.exists()
+        assert "--- markers" in copilot_skill.read_text(encoding="utf-8")
+
+        manager.unregister_agent_artifacts("auggie")
+
+        assert not auggie_skill.exists()
+        assert copilot_skill.exists()
+        metadata = manager.registry.get(extension_id)
+        assert skill_name in metadata.get("registered_skills", []), (
+            "tracking must survive while another marker-owned mirror exists"
+        )
+
+        assert manager.remove(extension_id) is True
+        assert not copilot_skill.exists()
+
     def test_extension_owned_skill_names_rejects_symlinked_candidate_directory(
         self, project_dir, temp_dir
     ):