Add direct gateway forwarding when VPN is off

Dockerfile

@@ -7,13 +7,12 @@ COPY dist /app/dist
 
 RUN if [ "${INSTALL_RUNTIME_DEPS}" = "true" ]; then \
         apt-get update \
-        && apt-get install -y --no-install-recommends ca-certificates curl iptables ipset iproute2 nodejs dumb-init \
+        && apt-get install -y --no-install-recommends ca-certificates curl iptables iproute2 nodejs dumb-init \
         && rm -rf /var/lib/apt/lists/*; \
     else \
         command -v dumb-init >/dev/null \
         && command -v node >/dev/null \
-        && command -v iptables >/dev/null \
-        && command -v ipset >/dev/null; \
+        && command -v iptables >/dev/null; \
     fi
 
 RUN if [ "${INSTALL_SINGBOX}" = "true" ]; then \
@@ -45,8 +44,6 @@ ENV PORT=3456 \
     PROXY_PORT=8080 \
     PROXY_BIND_IP=0.0.0.0 \
     TPROXY_PORT=7895 \
-    DIRECT_BYPASS_CACHE=false \
-    RULE_SET_DOWNLOAD_DETOUR=vpn \
     DATA_DIR=/var/lib/vpn-proxy \
     SING_BOX_CONFIG=/etc/sing-box/config.json \
     SING_BOX_CACHE=/var/lib/sing-box/cache.db