updates fish config

modules/fish/default.nix

@@ -194,6 +194,7 @@
         fish_add_path $ANDROID_HOME/platform-tools
         fish_add_path $HOME/.local/share/uv/tools
         rbenv init - | source
+        fnm env --use-on-cd --shell fish | source
       '';
     };
 
@@ -213,18 +214,14 @@
         setup_work
       end
 
-      # Third party integration not covered by
-      # home manager's enableFishIntegration
-      fnm env --use-on-cd --shell fish | source
-
       # Auto start tmux
       if status is-interactive; and not set -q TMUX
         if tmux list-sessions >/dev/null 2>&1
           # Attach to the first available session
-          tmux attach-session
+          tmux a
         else
           # Create a new session
-          tmux new-session -t default
+          tmux new-session -t main
         end
       end
     '';