Add update.sh, persist Go on PATH via profile.d

update.sh pulls the latest main, rebuilds, reinstalls, and restarts
the service in one step. install.sh/bootstrap.sh now also drop
/etc/profile.d/go-path.sh so Go stays on PATH in future shells, not
just within the running install script.

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

bootstrap.sh

@@ -49,6 +49,11 @@ if ! command -v go >/dev/null 2>&1; then
 	rm -f /tmp/go.tar.gz
 fi
 
+if [[ ! -f /etc/profile.d/go-path.sh ]]; then
+	echo 'export PATH="/usr/local/go/bin:$PATH"' > /etc/profile.d/go-path.sh
+	chmod 0644 /etc/profile.d/go-path.sh
+fi
+
 if ! command -v go >/dev/null 2>&1; then
 	echo "go still not found on PATH after install attempt (/usr/local/go/bin)." >&2
 	exit 1