feat: wire up post-update and post-install hooks

core/home/config/nomarchy/hooks/post-install.sample

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# This hook is called after the nomarchy-welcome wizard finishes successfully.
+# Use it to run any custom first-boot logic (e.g. cloning your dotfiles repo,
+# setting up SSH keys, or launching specific initial apps).
+
+# Example: Open the manual and show a notification
+# nomarchy-manual
+# notify-send "Welcome home" "Your Nomarchy system is ready to use."