Properties screen: expose stratum ports, TLS fingerprint, worker format

Entrypoint persists the generated TLS cert fingerprint so the
properties script can read it from the main volume. The screen
shows the active network, plaintext and TLS stratum ports, the
SHA-256 fingerprint for miner pinning, and the worker username
format (BTC address plus optional worker label).

docker_entrypoint.sh

@@ -134,6 +134,7 @@ if [[ "${TLS_ENABLED}" == "enabled" ]]; then
         chmod 600 "${TLS_DIR}/stratum.key" "${CERT}"
     fi
     FINGERPRINT=$(openssl x509 -in "${TLS_DIR}/stratum.crt" -noout -fingerprint -sha256 | cut -d= -f2)
+    printf '%s\n' "${FINGERPRINT}" > "${TLS_DIR}/fingerprint.txt"
     echo "kamado-entrypoint: stratum TLS SHA256 fingerprint: ${FINGERPRINT}"
 
     STUNNEL_CONF=/etc/stunnel/stratum.conf