Add Catppuccin Latte theme with a light terminal pane (#26)

Every existing theme keeps a dark terminal pane and normalizes the desktop's
light-scheme ANSI output onto it. Latte is the first light-pane theme: the
renderer gains a per-scheme table (ANSI palette, heading accent, and which
colors from the opposite scheme would vanish against the pane), the light
entry inverts the contrast normalization, and terminal views repaint their
cached frame when the theme changes.


Claude-Session: https://claude.ai/code/session_01NRdayBsqfSrkrJQy4X9Z2v

Co-authored-by: magneto <magneto.core.shadow@gmail.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>