Kopru: secili model hata verirse siradaki katman yapar

Hata kodu, baglanamama ve yarida kopma da siradaki katmana gider.
Siradakine gecilen adimda onceki cevap verilmez; son katman da
acilamazsa onun kendi hatasi gider.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/assets/codex-bridge/test_jev_denetim.py

@@ -241,6 +241,31 @@ class Akis(unittest.TestCase):
         self.assertEqual(self.opened, ["Katman-2", "Katman-3"])
         self.assertEqual(self.sent(), self.cevap["Katman-3"])
 
+    def test_an_error_of_the_selected_model_goes_to_the_next_layer(self):
+        self.h._denetimli_akis(None, "[1]", None, None, "yap", ["Katman-1", "Katman-2", "Katman-3", "Katman-4"], self.ac)
+        self.assertEqual(self.opened, ["Katman-1"])
+        self.assertEqual(self.sent(), self.cevap["Katman-1"])
+
+    def test_an_answer_cut_midway_goes_to_the_next_layer(self):
+        class Kopan(Yanit):
+            def read1(self, n):
+                if not self.parts:
+                    raise OSError("koptu")
+                return self.parts.pop(0)
+        self.h._denetimli_akis(Kopan(sse("yarim")), "[1]", None, None, "yap", ["Katman-2", "Katman-3", "Katman-4"], self.ac)
+        self.assertEqual(self.opened, ["Katman-2"])
+        self.assertEqual(self.sent(), self.cevap["Katman-2"])
+        self.assertNotIn(b"yarim", self.h.wfile.getvalue())
+
+    def test_when_no_layer_opens_the_blocked_answer_is_not_delivered(self):
+        self.puanlar = [{"ret": 0.9, "sart": 0.0}]
+        self.cevap.update({"Katman-2": None, "Katman-3": None, "Katman-4": None})
+        self.calistir(sse("Bunu yapamam."))
+        self.assertEqual(self.opened, ["Katman-2", "Katman-3", "Katman-4"])
+        self.assertNotIn(b"yapamam", self.h.wfile.getvalue())
+        self.assertIn(b"response.failed", self.sent())
+        self.assertIn(b"Katman-4: acilamadi", self.sent())            # the last layer's own error reaches the user
+
     def test_unreachable_jev_keeps_the_answer(self):
         self.puanlar = [None]
         body = sse("Bunu yapamam.")