Terminal widgets: no light mode, default palette forced dark

[max-wells]

Problem

Site-level UI (shadcn components) already supports dark/light via components/shared/theme-toggle.tsx and shared/hooks/use-theme-toggle.ts.

Terminal widget palettes (domains/terminal-themes/palettes/) don't follow the same pattern. Almost every theme in domains/terminal-themes/palettes/index.ts is dark-only. Only high-contrast-light is light. The default theme used for terminal demos is dark, so terminal widgets render dark regardless of site theme.

Expected

Terminal widget demos should react to light/dark mode the way shadcn components do:

• A light variant for the default terminal theme (or an explicit light/dark pairing mechanism), so switching the site theme also switches terminal widget appearance.
• Consider a mode: "dark" | "light" field per theme definition in TerminalThemeDefinition, or a paired light/dark theme map, so demos can resolve the right palette from the active site theme instead of hardcoding one palette.

Scope

• domains/terminal-themes/palettes/*
• domains/terminal-themes/types.ts
• wherever terminal demo components consume TERMINAL_THEME_MAP / THEMES

Out of scope

• Adding new theme palettes beyond what's needed for a light/dark pairing.