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_bind_count.fish

@@ -0,0 +1,28 @@
+function fish_bind_count
+    argparse 'h/help' 'z/zero' 'r/read' -- $argv
+    or return 1
+    if test -n "$_flag_help"
+        echo "Helper function to track count modifier with modal key bindings"
+        echo "Usage: $0 [-h] [-z] [DIGITS ...]"
+        return
+    end
+    if test -n "$_flag_zero" || not string match -rq '[1-9]\d*' "$fish_bind_count"
+        set -g fish_bind_count 0
+    end
+    # Iterate over given digits
+    for arg in $argv
+        for digit in (string split '' "$arg")
+            set -g fish_bind_count $(math "$fish_bind_count" \* 10 \+ "$digit")
+        end
+    end
+    if test -n "$_flag_read"
+        set -l count "$fish_bind_count"
+        set -g fish_bind_count 0
+        if test "$count" = 0
+            echo 1
+            return 1
+        else
+            echo "$count"
+        end
+    end
+end