feat(themes): add color derivation and themed app templates

Add script/omarchy-theme-color and expand omarchy-theme-set-templates to
derive a full palette from each theme's colors.toml, then render new
themed templates (shell, pi, vscode theme, gum, neovim, claude, hermes,
t3code) from it.

Adds backgrounds and palette updates for existing themes plus new themes
(last-horizon, lupine, solitude, tidewater-*, miasma, ...).

default/themed/rio.toml.tpl

@@ -1,56 +1,56 @@
 [colors]
 # Regular colors
 background = '{{ background }}'
-black = '{{ color0 }}'
-blue = '{{ color4 }}'
-cyan = '{{ color6 }}'
+black = '{{ background }}'
+blue = '{{ blue }}'
+cyan = '{{ cyan }}'
 foreground  = '{{ foreground }}'
-green = '{{ color2 }}'
-magenta = '{{ color5 }}'
-red = '{{ color1 }}'
-white = '{{ color15 }}'
-yellow = '{{ color11 }}'
+green = '{{ green }}'
+magenta = '{{ magenta }}'
+red = '{{ red }}'
+white = '{{ foreground }}'
+yellow = '{{ yellow }}'
 
 # Cursor
-cursor = '{{ cursor }}'
+cursor = '{{ bright_foreground }}'
 vi-cursor = '{{ accent }}'
 
 # Navigation
 # tabs and tabs-active set the inactive/active tab title colors.
 # Tab island backgrounds are derived from the window background color.
-tabs = '{{ color8 }}'
-tabs-active = '{{ color15 }}'
-split = '{{ color8 }}'
-split-active = '{{ color15 }}'
+tabs = '{{ muted }}'
+tabs-active = '{{ selection }}'
+split = '{{ muted }}'
+split-active = '{{ selection }}'
 
 # Search
-search-match-background = '{{ color12 }}'
-search-match-foreground = '{{ color15 }}'
-search-focused-match-background = '{{ color3 }}'
-search-focused-match-foreground = '{{ color15 }}'
+search-match-background = '{{ light_background }}'
+search-match-foreground = '{{ dark_foreground }}'
+search-focused-match-background = '{{ lighter_background }}'
+search-focused-match-foreground = '{{ dark_foreground }}'
 
 # Selection
 selection-foreground = '{{ selection_foreground }}'
 selection-background = '{{ selection_background }}'
 
 # Dim colors
-dim-black = '{{ color0 }}'
-dim-blue = '{{ color4 }}'
-dim-cyan = '{{ color6 }}'
+dim-black = '{{ background }}'
+dim-blue = '{{ blue }}'
+dim-cyan = '{{ cyan }}'
 dim-foreground = '{{ foreground }}'
-dim-green = '{{ color2 }}'
-dim-magenta = '{{ color5 }}'
-dim-red = '{{ color1 }}'
-dim-white = '{{ color15 }}'
-dim-yellow = '{{ color11 }}'
+dim-green = '{{ green }}'
+dim-magenta = '{{ magenta }}'
+dim-red = '{{ red }}'
+dim-white = '{{ foreground }}'
+dim-yellow = '{{ yellow }}'
 
 # Light colors
-light-black = '{{ color8 }}'
-light-blue = '{{ color12 }}'
-light-cyan = '{{ color14 }}'
-light-foreground = '{{ foreground }}'
-light-green = '{{ color10 }}'
-light-magenta = '{{ color13 }}'
-light-red = '{{ color9 }}'
-light-white = '{{ color15 }}'
-light-yellow = '{{ color11 }}'
+light-black = '{{ lighter_background }}'
+light-blue = '{{ bright_blue }}'
+light-cyan = '{{ bridht_cyan }}'
+light-foreground = '{{ bright_foreground }}'
+light-green = '{{ bright_green }}'
+light-magenta = '{{ bright_magenta }}'
+light-red = '{{ bright_red}}'
+light-white = '{{ bright_foreground }}'
+light-yellow = '{{ bright_yellow }}'