ZMK Corne base layer layout: leftmost column and thumb cluster assignments

ZMK Corne keymap: custom lt_tog hold-tap for layer thumb keys. RAISE layer (3): top row = ` 1–0 -; right home row = HOME UP END \ . .; right bottom row = PGUP LFT DWN RGT PGDN .; left rows = media/volume. ADJUST layer (2, repurposed LOWER slot): F1–F12 (F12 top-left), BT/RGB/layout-switch/bootloader (BOOT top-right). Left-inner thumb: &lt_tog ADJUST ADJUST. Right thumb (inner→middle→outer): &ht RCTRL RET / &kp LGUI / &lt_tog RAISE RAISE. Mid-right: &ht RSHFT SQT (tap ' / hold Right Shift). Bottom-right: &ht LC(LALT) RBKT (tap ] / hold Ctrl+Alt). Top-left: plain &kp TAB. Top-right: plain &kp ESC. Word movement: hold &mt LCTRL DEL + RAISE simultaneously (Ctrl+arrows on RAISE layer).