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

.gitignore

@@ -0,0 +1,14 @@
+# Debug Files/Folders
+OLD/
+*.OLD
+*.DISABLE
+*.DISABLED
+*_old
+
+# AI Session IDs
+.claude_session
+.gemini_session
+.remember/
+
+# Auto-managed by fish; contains machine-local state and universal vars
+fish_variables