Ported from grok build's TUI themes, whose palettes are defined in
crates/codegen/xai-grok-pager-render/src/theme/{groknight,grokday}.rs in
xai-org/grok-build -- they are compiled RGB constants, not extractable
from the shipped binary.
background uses grok's bg_terminal and cursor uses accent_user, which
grok sets over OSC 12 at startup, so a grok session sits flush against
the terminal. ANSI slots map onto the palette's own normal/bright pairs.
GrokNight's blue uses `blue` in both slots, as upstream TokyoNight does:
the palette's blue0 is a background blue and only reaches 2.96:1 on
#0a0a0a, which is too dim for ls output.
