Implement the theming layer for the interactive dashboard:
- tui/theme/theme.go: Theme struct with 14 semantic color roles
(Background, Surface, Border, BorderHover, TextDim, TextMuted,
TextPrimary, Accent, Green, Orange, Red, Blue, Purple, Yellow).
Four built-in themes:
* Flexoki Dark (default): warm, low-contrast palette designed for
extended reading. Teal accent (#3AA99F) on near-black background.
* Catppuccin Mocha: pastel warm tones with blue accent (#89B4FA)
on dark surface (#1E1E2E).
* Tokyo Night: cool blue/purple palette with blue accent (#7AA2F7)
on deep navy (#1A1B26).
* Terminal: ANSI 16-color only for maximum compatibility — maps
all roles to standard terminal colors (0-15), works correctly
in any terminal emulator regardless of true-color support.
Global Active variable holds the current theme. SetActive/ByName
enable runtime theme switching from the settings tab and setup
wizard.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
