🗻 Explore switchable theme: Kanagawa

[martinciu]

🎯 Goal

Add Kanagawa (Wave variant — the canonical dark, ink-wash inspired by
Hokusai's Great Wave off Kanagawa) as an eighth selectable theme via
the theme-set <name> fish switcher. Machinery landed in #185;
Gruvbox reference implementation in #193.

Variant pick: Wave is the default. Dragon is darker and more
saturated (recently popular). Lotus is light. Defer Dragon and Lotus.

🎨 Palette (Wave)

• Sumi Ink (bg): sumiInk0 #16161d, sumiInk1 #1f1f28, sumiInk2 #2a2a37, sumiInk3 #363646
• Fuji White (fg): fujiWhite #dcd7ba, oldWhite #c8c093
• Autumn (saturated): autumnRed #c4746e, autumnGreen #76946a, autumnYellow #dca561
• Spring (cooler): springBlue #7fb4ca, crystalBlue #7e9cd8, springViolet #957fb8, springGreen #98bb6c
• Wave (muted): waveAqua1 #6a9589, waveAqua2 #7aa89f, waveBlue1 #223249, waveBlue2 #2d4f67
• Other accents: sakuraPink #d27e99, peachRed #ff5d62, surimiOrange #ffa066, carpYellow #e6c384, samuraiRed #e82424 (bright)

📐 Architecture

Machinery is settled (#185). Slot in following the Gruvbox shape
(#193).

🛠️ Work breakdown

• `.config/themes/kanagawa.tmux` — semantic `@color_*` map
• `.config/themes/delta-kanagawa.gitconfig` — probe `bat --list-themes | grep -i kanagawa`; likely missing (Kanagawa isn't in bat's built-in catalogue as of 0.26). Vendor from `rebelot/kanagawa.nvim` — repo ships a `Kanagawa.tmTheme`.
• `.config/ghostty/theme-kanagawa.ghostty` — Ghostty does ship some Kanagawa variants (verify with `ghostty +list-themes | grep -i kanagawa`); vendor if missing
• `.config/starship-kanagawa.toml` — `pastel_rose = '#d27e99'` (sakuraPink)
• `.config/glow/glamour-kanagawa.json`
• `.config/gh-dash/config-kanagawa.yml`
• `.config/lnav/configs/installed/theme-kanagawa.json` — almost certainly needs vendoring (lnav 0.14 doesn't ship it)
• nvim: `rebelot/kanagawa.nvim` plugin spec; extend resolver
• Extend `theme-set.fish` switch (`case kanagawa`) + completion + `test-theme-switch.sh` round-trip

⚖️ Tradeoff

Win: muted ink-wash palette — the most distinct visual identity of
any theme in the rotation. Autumn-warm accents on cool sumi-ink
background reads like nothing else here.

Loss: probably the most vendoring work of the five candidate
themes. Expect to vendor a bat .tmTheme, an lnav theme-defs JSON, and
possibly a ghostty palette translation. Budget more time for the
mechanical "translate to tool X" passes.

🚦 Open questions

• Chip text inversion: muted autumnal palette → dark-on-accent
  (@color_light_fg = '#1f1f28' sumiInk1). Same logic as Mocha /
  Dracula / Gruvbox / Rose Pine.
• Wave vs Dragon for v1: Wave is the original; Dragon was added in
  2023 with deeper backgrounds and brighter accents. Wave is more
  recognised. Pick Wave; offer Dragon as follow-up.
• Unique-accent rule mapping (clean — six distinct hues):
  • session chip (blue): crystalBlue #7e9cd8 (deeper) or springBlue #7fb4ca (lighter)
  • active window pin (green): autumnGreen #76946a or springGreen #98bb6c
  • PR chip (orange): surimiOrange #ffa066
  • git main chip (violet): springViolet #957fb8
  • git wt chip (yellow): autumnYellow #dca561 or carpYellow #e6c384
  • red (defined but currently unused on bar): autumnRed #c4746e
• `pastel_rose`: sakuraPink #d27e99 is the literal Japanese-cherry-
  blossom pink in the palette — perfect match for the rose role.

🧠 Lessons

See consolidated lessons in #188 and the Gruvbox PR (#193). Expect a
higher vendoring component than Tokyo Night or Nord.

🔗 Links

• Homepage / nvim plugin: https://github.com/rebelot/kanagawa.nvim
• Palette spec: https://github.com/rebelot/kanagawa.nvim#color-palette