fix(kimi): preserve non-UTF-8 user skills (#3895)

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

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

src/specify_cli/integrations/kimi/__init__.py

@@ -317,7 +317,7 @@ def _is_speckit_generated_skill(skill_dir: Path) -> bool:
 
     try:
         content = skill_file.read_text(encoding="utf-8")
-    except OSError:
+    except (OSError, UnicodeError):
         return False
 
     if not content.startswith("---"):

tests/integrations/test_integration_kimi.py

@@ -199,6 +199,24 @@ class TestKimiTeardownLegacyCleanup:
 
         assert user_skill.exists()
 
+    def test_teardown_preserves_non_utf8_user_skill(self, tmp_path):
+        i = get_integration("kimi")
+
+        user_skill = (
+            tmp_path
+            / ".kimi"
+            / "skills"
+            / "speckit-user-owned"
+            / "SKILL.md"
+        )
+        user_skill.parent.mkdir(parents=True)
+        user_skill.write_bytes(b"\xff\xfe")
+
+        m = IntegrationManifest("kimi", tmp_path)
+        i.teardown(tmp_path, m)
+
+        assert user_skill.read_bytes() == b"\xff\xfe"
+
 
 class TestKimiCommandInvocation:
     """Kimi dispatch must use the native ``/skill:`` slash command."""