fix(presets): preserve files with invalid provenance

Use immutable-core legacy migration only when the provenance sidecar is absent.
If a sidecar is malformed or its hash does not match the live constitution,
treat the file as edited and preserve it.

Assisted-by: GitHub Copilot (model: GPT-5.6 Sol, autonomous)
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 1b2c095d-b45c-4d52-8d56-bd6121d96ab6

Author: BenBtg

src/specify_cli/presets/__init__.py

@@ -62,12 +62,11 @@ def _constitution_is_generated(
         try:
             metadata = json.loads(provenance.read_text(encoding="utf-8"))
         except (json.JSONDecodeError, UnicodeDecodeError):
-            metadata = {}
-        if (
+            return False
+        return (
             isinstance(metadata, dict)
             and metadata.get("sha256") == _content_sha256(content)
-        ):
-            return True
+        )
 
     # Older projects have no provenance sidecar. Only the immutable bundled or
     # source-checkout core template is safe to treat as generated.

tests/test_presets.py

@@ -2860,6 +2860,36 @@ def test_self_test_reseeds_exact_core_constitution(self, project_dir):
         assert "preset:self-test" in content, "placeholder constitution was not re-seeded"
         assert "[PROJECT_NAME]" not in content
 
+    @pytest.mark.parametrize(
+        "provenance_content",
+        [
+            '{"sha256": "does-not-match", "source": "old-preset"}\n',
+            "{not valid json",
+        ],
+        ids=["hash-mismatch", "malformed"],
+    )
+    def test_self_test_preserves_core_content_with_existing_invalid_provenance(
+        self, project_dir, provenance_content
+    ):
+        """A present invalid sidecar disables legacy core-template migration."""
+        resolver = PresetResolver(project_dir)
+        bundled_core = resolver._find_bundled_core(
+            "constitution-template", "template", ".md"
+        )
+        assert bundled_core is not None
+        memory = project_dir / ".specify" / "memory" / "constitution.md"
+        memory.parent.mkdir(parents=True, exist_ok=True)
+        memory.write_bytes(bundled_core.read_bytes())
+        (memory.parent / ".constitution-template.json").write_text(
+            provenance_content
+        )
+        original = memory.read_bytes()
+
+        manager = PresetManager(project_dir)
+        install_self_test_preset(manager)
+
+        assert memory.read_bytes() == original
+
     def test_self_test_preserves_mutable_project_core_copy(self, project_dir):
         """A project template copy does not establish generated provenance."""
         authored = "# Acme Organization Constitution\n\nOrganization policy.\n"