refactor: implement global syntax highlighting theme

conf.d/theme.fish

@@ -1,12 +1,12 @@
-# This file was created by fish when upgrading to version 4.3, to migrate
-# theme variables from universal to global scope.
-# Don't edit this file, as it will be written by the web-config tool (`fish_config`).
-# To customize your theme, delete this file and see
-#     help interactive#syntax-highlighting
-# or
-#     man fish-interactive | less +/^SYNTAX.HIGHLIGHTING
-# for appropriate commands to add to ~/.config/fish/config.fish instead.
-# See also the release notes for fish 4.3.0 (run `help relnotes`).
+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+#
+#          ╭──────────────────────────────────────────────────────────╮
+#          │                       Fish Theme                         │
+#          ╰──────────────────────────────────────────────────────────╯
+#
+# Catppuccin Mocha syntax highlighting colors.
+# These variables were migrated from the universal scope to global scope.
 
 set --global fish_color_autosuggestion 6c7086
 set --global fish_color_cancel f38ba8