feat: add Galaxy Theme with iTerm2 Color Compatibility

[JasperSui]

Discord username (optional)

N/A

Name of theme

Galaxy (iTerm2 Compatible)

How Has This Been Tested?

• Verified with python3 ./scripts/gen_theme_previews.py standard
• Tested color compatibility across Warp and iTerm2
• Validated prompt colors match between terminals

Notes

This theme addresses the color compatibility issue reported in warpdotdev/Warp#3951 where prompt colors differ between Warp and iTerm2. The theme has been specifically calibrated to ensure consistent color rendering across both terminals, particularly for:

• Path and prompt colors
• Terminal color palette
• Accent colors

The theme maintains Galaxy's signature look while ensuring color consistency between Warp and iTerm2 environments.