Rename bg/fg palette keys to background/foreground

The canonical colors.toml keys are now background/foreground, including
all permutations (dark_background, darker_background, lighter_background,
dark_foreground, light_foreground, bright_foreground). The old short
names are gone entirely, not kept as aliases; legacy alacritty-generated
themes still resolve through the ANSI color0/color7 fallback.

Theme files are also regrouped: accent/selection/muted first, then the
backgrounds, then the foregrounds, then the named colors.

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

docs/omarchy-shell.md

@@ -141,9 +141,9 @@ sizing in `themes/<name>/shell.toml`. Defaults are generated from
 `default/themed/shell.toml.tpl`; a theme may also drop a hand-written
 `shell.toml` next to its `colors.toml` to replace the generated file.
 
-`colors.toml` uses `fg` and `bg` for the foundational text/background
-palette. The shell exposes those to QML as `Color.foreground` and
-`Color.background`, so shell roles still use the readable role names.
+`colors.toml` uses `foreground` and `background` for the foundational
+text/background palette, exposed to QML as `Color.foreground` and
+`Color.background`.
 
 The shell exposes these tokens to QML via two singletons in
 `qs.Commons`:

docs/theming.md

@@ -30,36 +30,50 @@ built-in template, the built-in output is skipped.
 
 ## `colors.toml`
 
-`colors.toml` provides the palette keys used by templates. Common keys are:
+`colors.toml` provides the palette keys used by templates. Keys are grouped
+semantic-first: accent/selection/muted, then the backgrounds, then the
+foregrounds, then the named colors:
 
 ```toml
-bg                   = "#1a1b26"
-fg                   = "#a9b1d6"
-accent               = "#7aa2f7"
-selection            = "#292e42"
-red                  = "#f7768e"
-blue                 = "#7aa2f7"
+mode = "dark"
+
+accent = "#7aa2f7"
+selection = "#292e42"
+muted = "#414868"
+
+background = "#1a1b26"
+dark_background = "#13141c"
+darker_background = "#0e0e14"
+lighter_background = "#24283b"
+
+foreground = "#a9b1d6"
+dark_foreground = "#565f89"
+light_foreground = "#b4bee6"
+bright_foreground = "#c0caf5"
+
+red = "#f7768e"
+blue = "#7aa2f7"
 ```
 
 Any key can be referenced from a template with `{{ key }}`. The foundational
 shell palette is loaded from:
 
-- `fg` — primary readable text color
-- `bg` — primary background color
+- `foreground` — primary readable text color
+- `background` — primary background color
 - `accent` — preferred when present; otherwise some places fall back to
   `color4`
+- `muted` — de-emphasized elements (comments, placeholders, dividers); also
+  serves as ANSI `color8`
 - `urgent` / `red` / `color1`
 
-For older user themes and templates, `foreground` aliases to `fg` and
-`background` aliases to `bg`.
-
-The neutral ramp is centered on `bg -> bright_fg`. Dark themes should read from
-darkest to lightest; light themes should read from lightest to darkest. Terminal
-and editor cursors use `bright_fg`; there is no separate cursor palette key.
-`selection` is the text-selection background stop in that ramp; Omarchy derives
-`selection_background = selection` and `selection_foreground = bright_fg`. Use
-`omarchy dev theme-preview [theme]` to inspect that ramp, including `dark_bg`,
-`darker_bg`, and a selected-text sample.
+The neutral ramp is centered on `background -> bright_foreground`. Dark themes
+should read from darkest to lightest; light themes should read from lightest to
+darkest. Terminal and editor cursors use `bright_foreground`; there is no
+separate cursor palette key. `selection` is the text-selection background stop
+in that ramp; Omarchy derives `selection_background = selection` and
+`selection_foreground = bright_foreground`. Use
+`omarchy dev theme-preview [theme]` to inspect that ramp, including
+`dark_background`, `darker_background`, and a selected-text sample.
 
 ## Template placeholders
 
@@ -82,8 +96,8 @@ For a color key such as `accent = "#7aa2f7"`:
 percentage:
 
 ```text
-{{ mix bg fg 15% }}
-{{ mix_strip bg accent 0.35 }}
+{{ mix background foreground 15% }}
+{{ mix_strip background accent 0.35 }}
 {{ mix_rgb color0 color7 50 }}
 ```