Greet the first login with a keybindings toast again

Opening the cheatsheet outright put a menu in front of someone who had not
asked for one, and it blocked first run until they dismissed it. Go back to a
toast that opens the same menu when clicked.

The body carries real newlines now. It was written with a literal \n, which the
card renders as the two characters rather than a line break.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

install/user/first-run/keybindings.sh

@@ -1,4 +0,0 @@
-# Greet the first login with the cheatsheet itself rather than a toast
-# pointing at it. The menu blocks until it is answered, and dismissing it
-# exits non-zero, which is a normal way to close it.
-omarchy-menu-keybindings || true

install/user/first-run/welcome.sh

@@ -0,0 +1,5 @@
+# Real newlines, not a literal \n: the card renders the body as it arrives, and
+# elides past three lines.
+omarchy-notification-send -u critical -g  "Learn Keybindings" \
+  $'Super + K for cheatsheet.\nSuper + Space for Omarchy Menu.' \
+  --exec omarchy-menu-keybindings