feat: Gruvbox Dark theme for Yazi 26.9, icons included

Panel chrome, filetype colours and the full 725-entry icon table.

The icon table is Yazi's preset with every glyph colour remapped onto the
Gruvbox palette: nearest neighbour in Oklab with lightness weighted down so
hue drives the match, chromatic and greyish sources matched from separate
pools, and target tones below 3:1 contrast on #282828 excluded. 221 upstream
colours collapse onto 19 Gruvbox tones, dimmest icon at 3.48:1.

regen-icons.py reproduces the mapping against a newer Yazi preset.

Uses the current schema ([mgr]/[tabs]/[pick]/[cmp]), not the pre-25.x one.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

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+# yazi-gruvbox
+
+A [Gruvbox Dark](https://github.com/morhetz/gruvbox) `theme.toml` for
+[Yazi](https://github.com/sxyazi/yazi) — including the **icon table**, so the
+devicons in front of your files stop looking like a paint spill on an otherwise
+muted colour scheme.
+
+Written against **Yazi 26.9**. It uses the current schema (`[mgr]`, `[tabs]`,
+`[pick]`, `[cmp]`, `[indicator]`, …), not the pre-25.x one — older Gruvbox
+themes floating around still use `[manager]` and `[select]` and will throw
+errors on a current Yazi.
+
+## What it covers
+
+Panel chrome, status bar, tabs, mode indicator, which-key, confirm/spot/notify
+popups, picker, input, completion, task manager, help — plus:
+
+**File and directory names** (`[filetype]`):
+
+| | |
+|---|---|
+| directories | `#83a598` blue |
+| regular files | `#ebdbb2` fg1 |
+| executables | `#b8bb26` green |
+| archives | `#fe8019` orange |
+| images | `#fabd2f` yellow |
+| audio / video | `#d3869b` purple |
+| PDF / doc | `#8ec07c` aqua |
+| orphan symlinks | red background |
+
+**Icons** (`[icon]`): all 725 entries of Yazi's preset table, every glyph colour
+remapped to its nearest Gruvbox tone.
+
+## How the icon colours were derived
+
+Yazi's preset ships 725 icon entries using 221 distinct colours from the
+nvim-tree/devicons palette — saturated web colours that clash badly with
+Gruvbox's muted ground.
+
+`regen-icons.py` maps each of them onto the Gruvbox palette:
+
+- **Nearest neighbour in Oklab**, so the match is perceptual rather than a naive
+  RGB distance.
+- **Lightness weighted down (0.7)** in the distance metric, so *hue* drives the
+  result. Docker blue stays blue, Ruby red stays red, instead of everything
+  collapsing toward whatever tone happens to be equally bright.
+- **Chromatic and greyish sources are matched from separate pools** (split at
+  Oklab chroma 0.04). Without that split a vivid magenta can land on grey, and
+  white can land on orange.
+- **Low-contrast targets are excluded.** `#cc241d` (2.69:1) and `#7c6f64`
+  (3.03:1) on `#282828` were dropped from the target palette — icons are
+  non-text, so 3:1 is the bar. The dimmest icon now sits at **3.48:1**.
+
+221 colours end up on 19 Gruvbox tones. Icons stay colourful and stay
+distinguishable; they just stop shouting.
+
+## Install
+
+```sh
+git clone https://git.opennerds.org/templis/yazi-gruvbox
+cp yazi-gruvbox/theme.toml ~/.config/yazi/theme.toml
+```
+
+`theme.toml` overrides Yazi's built-in `theme-dark.toml`; anything it does not
+set keeps the default.
+
+### Optional: Gruvbox syntax highlighting in previews
+
+Not shipped here — the usual Gruvbox `.tmTheme` for Yazi is AGPL-3.0 and would
+pull this repository along with it (see `THIRD-PARTY.md`). To get it:
+
+```sh
+curl -o ~/.config/yazi/Gruvbox-Dark.tmTheme \
+  https://raw.githubusercontent.com/poperigby/gruvbox-dark-yazi/main/Gruvbox-Dark.tmTheme
+```
+
+Then uncomment in `theme.toml`:
+
+```toml
+[mgr]
+syntect_theme = "~/.config/yazi/Gruvbox-Dark.tmTheme"
+```
+
+## Keeping the icon table current
+
+The `[icon]` block **replaces** Yazi's preset table wholesale. Icons added by
+later Yazi releases will not show up until it is regenerated:
+
+```sh
+git clone --depth 1 https://github.com/sxyazi/yazi
+awk '/^\[icon\]/{f=1} f' yazi/yazi-config/preset/theme-dark.toml > icons-src.toml
+./regen-icons.py icons-src.toml      # writes icon-gruvbox.toml
+```
+
+Then replace the `[icon]` block in `theme.toml` with the generated file. The
+script prints which Gruvbox tone each source colour landed on.
+
+## Licence
+
+MIT — see `LICENSE`. Derived icon data is MIT as well; notices in
+`THIRD-PARTY.md`.