Increase platform abstraction cohesion

core/clients/transport.py

@@ -776,6 +776,14 @@ async def send_message_raw(
     Unified outbound send path used by models/views/UR.
     """
     service_key = _service_key(service)
+    if _capability_checks_enabled() and not supports(service_key, "send"):
+        reason = unsupported_reason(service_key, "send")
+        log.warning(
+            "capability-check failed service=%s feature=send: %s",
+            service_key,
+            reason,
+        )
+        return False
     if service_key == "signal":
         prepared_attachments = await prepare_outbound_attachments(
             service_key, attachments or []