feat(layout): reduce default MAM_MIN_PANE_COLS to 40 for single workspace 2xK multi-pane tiling

.mam.env.example

@@ -129,8 +129,8 @@
 # SKS_EMPTY_GIVEUP=3
 
 # Minimum columns a pane must retain after a vertical split (2xK layout engine).
-#default: 60
-# MAM_MIN_PANE_COLS=60
+#default: 40
+# MAM_MIN_PANE_COLS=40
 
 # Minimum rows a pane must retain after a horizontal split (2xK layout engine).
 #default: 20