Keycode processing migration+stubs.

quantum/process_keycode/process_connection.h

@@ -0,0 +1,9 @@
+// Copyright 2024 Nick Brassel (@tzarc)
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "action.h"
+
+bool process_connection(uint16_t keycode, keyrecord_t *record);