feat(fish): ✨ Add helix key bindings from https://github.com/sshilovsky/fish-helix/tree/main

Add comprehensive helix-like modal key bindings system for fish shell
with:
- New `fish_helix_key_bindings` function with helix-inspired navigation
- Modal editing support with count modifiers via `fish_bind_count`
- Visual mode prompt indicator via `fish_default_mode_prompt`
- Enhanced clipboard integration with proper notification formatting

The implementation provides vim/helix-style modal editing while
maintaining
fish shell compatibility and includes proper mode indicators, count
tracking,
and seamless integration with existing fish key binding systems.

home/.config/fish/functions/fish_user_key_bindings.fish

@@ -6,7 +6,7 @@ function fish_user_key_bindings
     # Without --no-erase fish_vi_key_bindings will default to
     # resetting all bindings.
     # The argument specifies the initial mode (insert, "default" or visual).
-    fish_vi_key_bindings --no-erase insert
+    fish_helix_key_bindings --no-erase insert
 
     # Nullify fzf default keybindings
     bind \cT '' -M insert