Name the received JSON type in non-object params errors

Keep -32602 and existing validation order; tell callers to send the object itself.
Cover host routing, stdout fast paths, SDK calls and generated dispatch.

Card: SAU-317

cli/tests/plugins/probe/src/main.rs

@@ -470,6 +470,10 @@ fn dispatch(request: &Value, lines: &mut Lines) -> Option<Value> {
         "network" => network(params),
         "read" => read_file(params),
         "write" => write_file(params),
+        "raw_call" => {
+            send(params.clone());
+            receive(lines)
+        }
         "call" => outgoing_call(params, lines),
         "lock" => lock(params, lines),
         _ => {