feat: initial fish shell configuration

- Core config layered on CachyOS base with Catppuccin Mocha theming
- Fisher plugins: fzf.fish, catppuccin, autopair, replay, puffer-fish, magic-enter, spark
- Smart CLI wrappers with fallbacks (bat, lsd, btop, dust, prettyping)
- Custom functions: git, docker, network, kitty, AI session management
- Extensive abbreviation system for keyboard-driven workflows
- Secrets/local sourcing pattern for private and machine-specific config
- README with full documentation and personalization guide
- AGPLv3+ license with copyright headers on all source files

functions/split.fish

@@ -0,0 +1,22 @@
+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+function split --description 'Run a command in a new Kitty split'
+    set -l location hsplit
+
+    switch $argv[1]
+        case -h --horizontal
+            set location hsplit
+            set -e argv[1]
+        case -v --vertical
+            set location vsplit
+            set -e argv[1]
+    end
+
+    if test (count $argv) -gt 0
+        # Set HIDE_GREETING=1 before fish starts
+        kitty @ launch --location=$location --cwd=$PWD env HIDE_GREETING=1 fish -c "$argv; exec fish"
+    else
+        kitty @ launch --location=$location --cwd=$PWD env HIDE_GREETING=1 fish -c "exec fish"
+    end
+end