fix(assessment): reject ambiguous trust keyrings

tests/test_capability_fit_review.py

@@ -272,7 +272,7 @@ class CapabilityFitReviewTests(unittest.TestCase):
         )
         self.assertTrue(report["proof_scope"]["published_keyring_hash"]["valid"])
 
-    def test_locally_pinned_rotation_keys_follow_core_status_semantics(self) -> None:
+    def test_locally_pinned_rotation_keys_fail_closed(self) -> None:
         keys = trusted_keys_from_keyring(
             {
                 "keys": [
@@ -288,6 +288,38 @@ class CapabilityFitReviewTests(unittest.TestCase):
             {"legacy": "base64-key"},
             trusted_keys_from_keyring({"legacy": "base64-key"}),
         )
+        self.assertEqual(
+            {},
+            trusted_keys_from_keyring(
+                {
+                    "keys": [
+                        {
+                            "key_id": "typo",
+                            "status": "retierd",
+                            "public_key": "unsafe",
+                        }
+                    ]
+                }
+            ),
+        )
+        self.assertEqual(
+            {},
+            trusted_keys_from_keyring(
+                {
+                    "keys": [
+                        {"key_id": "duplicate", "public_key": "a"},
+                        {"key_id": "duplicate", "public_key": "b"},
+                    ]
+                }
+            ),
+        )
+        self.assertEqual({}, trusted_keys_from_keyring({"keys": "invalid"}))
+        self.assertEqual(
+            {},
+            trusted_keys_from_keyring(
+                {"keys": [{"key_id": " ", "public_key": "unsafe"}]}
+            ),
+        )
 
     def test_schema_error_blocks_before_comparison(self) -> None:
         assessment = deepcopy(self.assessment)