Add keybind to change RGB effect

keymaps/custom/os_detect.c

@@ -4,6 +4,9 @@
 
 #include "os_mode.h"
 
+// System76 per-layer RGB state (no header available)
+void system76_ec_rgb_layer(layer_state_t layer_state);
+
 os_mode_t os_mode = OS_MODE_NONE;
 bool os_mode_manual = false;
 static bool os_detected = false;
@@ -45,6 +48,6 @@ void matrix_scan_user(void) {
     // Restore default RGB animation after 500ms indicator flash
     if (flash_start && timer_elapsed32(flash_start) > 500) {
         flash_start = 0;
-        rgb_matrix_reload_from_eeprom();
+        system76_ec_rgb_layer(layer_state);
     }
 }