chore(config): clean up and reorganize configuration files

dot_config/ghostty/config

@@ -1,12 +1,12 @@
 # Font Configuration
-font-size = 12.5
+font-size = 13
 font-family = Victor Mono NF
 background-blur = true
 
 # Window Configuration
 window-decoration = false
-window-padding-x = 12
-window-padding-y = 12
+window-padding-x = 0
+window-padding-y = 0
 background-opacity = 0.9
 
 # Cursor Configuration
@@ -37,6 +37,10 @@ gtk-titlebar = false
 
 quit-after-last-window-closed = false
 quit-after-last-window-closed-delay = 5m
+# Every window and tab attaches to the tmux session "main", creating it
+# when missing, so closing Ghostty detaches instead of killing the shells.
+command = tmux new-session -A -s main
+
 # Shell integration
 shell-integration = detect
 shell-integration-features = cursor,sudo,title,no-cursor