tests: close 10 high-priority contract gaps (loop-gate-reason, backend-cascade-call, read-framed-message, snapshot/rollback, ingest-ast, memory-object-get)

lisp/core-loop-reason.lisp

@@ -251,3 +251,32 @@ sorted by priority (highest first). Returns a rejection plist or the action."
          (result (cognitive-verify candidate signal)))
     (is (eq :approval-required (getf result :level)))
     (is (eq :EVENT (getf result :type)))))
+
+(test test-loop-gate-reason-passthrough
+  "Contract 2: non-user-input sensors pass through loop-gate-reason unchanged."
+  (let* ((signal '(:type :EVENT :payload (:sensor :heartbeat) :meta (:source :system)))
+         (result (loop-gate-reason signal)))
+    (is (not (null result)))))
+
+(test test-loop-gate-reason-sets-status
+  "Contract 2: loop-gate-reason sets :status on :user-input signals."
+  (clrhash passepartout::*skill-registry*)
+  (let* ((signal (list :type :EVENT :payload (list :sensor :user-input :text "test")))
+         (result (loop-gate-reason signal)))
+    (is (member (getf result :status) '(:reasoned :requires-approval)))))
+
+(test test-backend-cascade-no-backends
+  "Contract 4: empty cascade returns :LOG failure."
+  (let ((result (backend-cascade-call "test" :cascade '())))
+    (is (eq :LOG (getf result :type)))
+    (is (search "exhausted" (getf (getf result :payload) :text) :test #'char-equal))))
+
+(test test-backend-cascade-with-mock
+  "Contract 4: backend-cascade-call returns content from first successful backend."
+  (let ((passepartout::*backend-registry* (make-hash-table :test 'equal)))
+    (setf (gethash :mock-backend passepartout::*backend-registry*)
+          (lambda (prompt sp &key model)
+            (declare (ignore prompt sp model))
+            (list :status :success :content "mock-response")))
+    (let ((result (backend-cascade-call "hello" :cascade '(:mock-backend))))
+      (is (string= "mock-response" result)))))