fix: prevent mixed-version pushy feedback

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a03397-4d51-7fd1-8ff2-946eb22ea2bc

tests/test_tmux_integration.py

@@ -369,6 +369,23 @@ def test_real_tmux_hash_route_pushes_once_without_feedback(tmp_path, monkeypatch
         assert f"AGENT:{expected}" in target_capture
         assert store.list()[0]["state"] == "injected"
 
+        legacy_envelope = (
+            f"#railiance-platform: Hello! [{row['message_id']}]"
+        )
+        manager._run(
+            "send-keys",
+            "-t",
+            f"{session}:activity-core",
+            "-l",
+            "--",
+            legacy_envelope,
+        )
+        manager._run(
+            "send-keys", "-t", f"{session}:activity-core", "Enter"
+        )
+        time.sleep(0.1)
+        assert len(store.list()) == 1
+
         service._deliver_once()
         time.sleep(0.1)
         assert len(store.list()) == 1