Add extras post-copy flow for RAM and Hekate-Pro selection.

Copy sd:/extras from the pack, prompt for RAM and Hekate/AMS choices, persist them in config.ini, apply Pro/8GB payloads, then remove extras/. Use safe config.ini I/O and Joy-Con input clearing between menus.

bdk/input/joycon.c

@@ -721,6 +721,12 @@ void jc_deinit()
 	clock_disable_uart(UART_C);
 }
 
+/* Drop current button state without power-cycling the Joy-Cons. */
+void jc_clear_input(void)
+{
+	jc_gamepad.buttons = 0;
+}
+
 static void jc_init_conn(joycon_ctxt_t *jc)
 {
 	if (((u32)get_tmr_ms() - jc->last_received_time) > 1000)