feat: add Claude Dark and Claude Light themes

[Astro-Han]

Description

Add Claude Dark and Claude Light themes inspired by Anthropic's Claude (claude.ai) design system.

Design principles

• Warm neutral palette — all grays carry a subtle warm tint (blue channel 1-3 points lower than red/green), matching Claude's "unfired clay" brand aesthetic designed by Geist Studio
• Brand-anchored ANSI colors — normal colors derived from Claude's semantic color tokens (error, success, warning, info, violet); bright colors from the official CSS color ramp 200 stops
• Pixel-verified backgrounds — background and foreground colors sampled directly from claude.ai screenshots, not just CSS variables
• Terra cotta accent — cursor uses Claude's brand-clay (#d97757)

More details on the color research: https://github.com/anthropics/skills/blob/main/skills/brand-guidelines/SKILL.md

New Theme

Submitted Claude Dark.yml and Claude Light.yml in YAML format.

[mbadolato]

Thank you!