Themes:
- Add leuchtturm theme (fountain pen ink on cream paper, brass/leather dark)
- Add per-theme syntax palettes for leuchtturm, tufte, and everforest
- Fix static inline globals giving each TU its own copy of gCurrentTheme
and gBackgroundMode (changed to inline for proper C++17 linkage)
- :background with no args now shows current mode
Font zoom:
- CMD-=/CMD--/CMD-0 to increase/decrease/reset font size
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Warm cream paper, near-black ink, zero rounding, minimal chrome,
restrained dark red and navy accents following Tufte's design principles.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
