fix(x11,docs): use busctl+pkcheck for polkit power actions, increase st font to 18px, and format README overview list

overlay/rootfs/usr/bin/sxmo_power.sh

@@ -14,18 +14,29 @@ usage() {
 run_polkit_login1() {
   method="$1"
   python3 - "$method" <<'PYEOF' >/dev/null 2>&1
-import os, pty, sys
+import os, pty, select, sys
 method = sys.argv[1]
+if method == "Reboot":
+  acts = "org.freedesktop.login1.reboot org.freedesktop.login1.reboot-multiple-sessions org.freedesktop.login1.reboot-ignore-inhibit"
+else:
+  acts = "org.freedesktop.login1.power-off org.freedesktop.login1.power-off-multiple-sessions org.freedesktop.login1.power-off-ignore-inhibit"
 cmd = (
   "pkttyagent --process $$ & AG=$!; sleep 0.15; "
-  "dbus-send --system --print-reply --dest=org.freedesktop.login1 "
-  "/org/freedesktop/login1 org.freedesktop.login1.Manager." + method + " boolean:true; "
-  "RC=$?; kill $AG 2>/dev/null; exit $RC"
+  "for act in " + acts + "; do "
+  "pkcheck --action-id $act --process $$ -u >/dev/null 2>&1 || true; "
+  "done; "
+  "kill $AG 2>/dev/null || true; "
+  "exec busctl call --allow-interactive-authorization=true "
+  "org.freedesktop.login1 /org/freedesktop/login1 "
+  "org.freedesktop.login1.Manager " + method + " b true"
 )
 pid, fd = pty.fork()
 if pid == 0:
   os.execlp("sh", "sh", "-c", cmd)
 while True:
+  r, _, _ = select.select([fd], [], [], 3.0)
+  if not r:
+    break
   try:
     d = os.read(fd, 1024)
     if not d: