feat(ghostty-tmux): add smart tmux wrapper script

Launch tmux only on first Ghostty instance,
avoiding nested tmux sessions.
Remove direct tmux command from Ghostty config
in favor of the wrapper approach.

Author: sabertazimi

dot_config/ghostty/config

@@ -55,4 +55,3 @@ keybind = alt+h=goto_split:left
 keybind = alt+j=goto_split:down
 keybind = alt+k=goto_split:up
 keybind = alt+l=goto_split:right
-command = tmux attach || tmux

dot_config/niri/dms/binds.kdl

@@ -11,7 +11,7 @@ binds {
     Mod+Shift+Slash { show-hotkey-overlay; }
 
     // === Application Launchers ===
-    Mod+T hotkey-overlay-title="Open Terminal" { spawn "ghostty"; }
+    Mod+T hotkey-overlay-title="Open Terminal" { spawn "sh" "-c" "$HOME/.local/bin/ghostty-tmux.sh"; }
     Mod+D hotkey-overlay-title="Application Launcher" {
         spawn "dms" "ipc" "call" "spotlight" "toggle";
     }

dot_local/bin/executable_ghostty-tmux.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+if pgrep -x "ghostty" >/dev/null; then
+  ghostty &
+else
+  ghostty -e sh -c "tmux attach || tmux" &
+fi