perf(perception): borrow contiguous image buffers for local IPC

tests/test_perception_joint_pilot.py

@@ -114,6 +114,43 @@ def test_ipc_preserves_binary_and_rejects_oversized_header(pilot):
         ipc.receive(io.BytesIO((65537).to_bytes(4, "little")))
 
 
+def test_ipc_borrows_payload_without_concatenation_and_handles_partial_writes(pilot):
+    ipc = pilot("pilot_ipc")
+    payload = np.arange(24, dtype=np.uint8).reshape(2, 4, 3)
+    calls, written = [], bytearray()
+
+    class Writer:
+        def write(self, value):
+            calls.append(value)
+            size = min(7, len(value))
+            written.extend(value[:size])
+            return size
+
+        def flush(self):
+            pass
+
+    ipc.send(Writer(), {"op": "infer"}, memoryview(payload))
+    body = payload.tobytes()
+    header = json.dumps({"op": "infer", "payload_bytes": len(body)}).encode()
+    assert written == len(header).to_bytes(4, "little") + header + body
+    assert any(value.obj is payload for value in calls)
+    assert all(isinstance(value, memoryview) for value in calls)
+    assert ipc.receive(io.BytesIO(written)) == ({"op": "infer"}, body)
+
+
+@pytest.mark.parametrize("result", [0, None, -1, True, 100000])
+def test_ipc_rejects_invalid_write_progress(pilot, result):
+    with pytest.raises(EOFError, match="progress"):
+        pilot("pilot_ipc").send(SimpleNamespace(write=lambda _: result), {}, b"x")
+
+
+def test_ipc_rejects_noncontiguous_payload_before_writing(pilot):
+    stream = io.BytesIO()
+    with pytest.raises(TypeError):
+        pilot("pilot_ipc").send(stream, {}, memoryview(np.arange(8, dtype=np.uint8)[::2]))
+    assert stream.getvalue() == b""
+
+
 def test_nearest_rank_tail_metrics_keep_outlier(pilot):
     metrics = pilot("run_joint_pilot").distribution([1] * 99 + [200])
     assert metrics["p99"] == 1