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>

themes/hackerman/colors.toml

@@ -1,18 +1,20 @@
 mode = "dark"
 
 accent = "#82FB9C"
-hyprland_active_border = "rgba(26a269ee) rgba(2ec27eee) 45deg"
-
-bg = "#0B0C16"
-dark_bg = "#080910"
-darker_bg = "#06060c"
-lighter_bg = "#151828"
 selection = "#1f253a"
 muted = "#2d3450"
-dark_fg = "#6a6e95"
-fg = "#ddf7ff"
-light_fg = "#b5c5db"
-bright_fg = "#ddf7ff"
+
+background = "#0B0C16"
+dark_background = "#080910"
+darker_background = "#06060c"
+lighter_background = "#151828"
+
+foreground = "#ddf7ff"
+dark_foreground = "#6a6e95"
+light_foreground = "#b5c5db"
+bright_foreground = "#ddf7ff"
+
+hyprland_active_border = "rgba(26a269ee) rgba(2ec27eee) 45deg"
 
 red = "#50f872"
 yellow = "#50f7d4"