Introduces LCK_FN1–LCK_FN4, LCK_CTL, and LCK_BASE custom keycodes that
toggle a layer into a locked state so it stays active after momentary keys
are released. A second press on the same lock key or pressing LCK_BASE
clears all locks and returns to BASE.
Implements rgb_matrix_indicators_advanced_user to colour the ESC key
(LED 0) based on the current layer: dark on BASE, blue on FN1, green
on FN2, orange on FN3, purple on FN4, and red on KEEB_CTL.
Adds a three-key combo (, . /) that fires TO(BASE), providing an
emergency escape hatch when stuck on an unknown layer. COMBO_ONLY_FROM_LAYER
is set to 0 in the keymap config.h so keycodes are always resolved from
BASE, making the combo reliable regardless of the active layer.
rootiest
