chore(fish): drop redundant ssh-auth-sock hook

The symlink refresh and export already happen in config/bash/profile,
and tmux.conf sets SSH_AUTH_SOCK globally, so the fish conf.d copy was
a duplicate.

config/fish/conf.d/02-ssh-auth-sock.fish

@@ -1,20 +0,0 @@
-# Create a predictable symlink to the current SSH auth socket.
-# tmux forces SSH_AUTH_SOCK to ~/.ssh/ssh_auth_sock globally
-# (see config/tmux/tmux.conf), so this symlink must exist for every
-# interactive shell -- not just bash login shells.
-#
-# For herdr (which lacks tmux's setenv -g): if we inherit a real
-# SSH_AUTH_SOCK, update the symlink. Then always export the symlink
-# path so new panes that didn't inherit the env still pick it up.
-set -l auth_sock "$HOME/.ssh/ssh_auth_sock"
-
-# If we have a real socket (not the symlink), refresh the symlink
-if set -q SSH_AUTH_SOCK; and test "$SSH_AUTH_SOCK" != "$auth_sock"; and test -S "$SSH_AUTH_SOCK"
-    mkdir -p "$HOME/.ssh"
-    ln -sf "$SSH_AUTH_SOCK" "$auth_sock"
-end
-
-# Always export the symlink path if it points to a live socket
-if test -S "$auth_sock"
-    set -gx SSH_AUTH_SOCK "$auth_sock"
-end