Add MQTT handover controller and systemd installer

meshcore-phone-mode.ini.example

@@ -0,0 +1,12 @@
+# Zorruno — MeshCore Phone App Mode v1.0 — 2026-10-03
+# Copy to /etc/meshcore-phone-mode.ini; installer creates it with mode 0600.
+# Enter the MQTT credentials locally. Values are literal (no surrounding quotes).
+# Keep username/password blank only if your broker permits anonymous access.
+[mqtt]
+host = 127.0.0.1
+port = 1883
+username =
+password =
+
+[controller]
+poll_seconds = 15