RGDS ROCKNIX - BOTTOM SCREEN UNIVERSAL KEYBOARD

RGDS ROCKNIX - BOTTOM SCREEN UNIVERSAL KEYBOARD

Three fixes in v5.1:
2×2 big-pixel grid — Every visual element now snaps to a 2-screen-pixel grid. PX=2 is the base unit, so BEVEL = 3PX = 6 screen pixels (3 big pixels), NOTCH = 2PX = 4 screen pixels (2 big pixels), GAP = 2PX = 4 screen pixels. Font dot scales are always even (6 for letters, 4 for short labels, 2 for long text). Key rects, text positions, bevel edges, and the brightness bar all snap to // PX * PX. The pressed-key text shift is 1 big pixel (PX=2) instead of 1 screen pixel.
No more black bar — All five layouts now fill exactly 480px top to bottom. Number row is taller (h=56, up from 48) for easier tapping, space row and utility row are each h=78 (up from 64 and 52). Row Y positions: 0→58→146→234→322→402, with the utility row ending precisely at y=402+78=480.
Brightness targets DSI-1 — Replaced the sysfs /sys/class/backlight/ approach (which was hitting the top screen) with swaymsg 'output DSI-1 brightness 0.60' which targets the bottom screen specifically. Brightness is now a float 0.0–1.0, stored in settings, and applied on startup. Each tap steps by 0.08.