feat(packaging): add polkit policy, systemd units and PKGBUILD

systemd/prx-reapply.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=Re-apply prx proxy routing
+Documentation=man:prx(1)
+After=network-online.target
+Wants=network-online.target
+# Only run when prx was enabled (state snapshot exists).
+ConditionPathExists=/run/prx/state.json
+
+[Service]
+Type=oneshot
+# `prx on` is idempotent: it re-detects the gateway and refreshes the rules.
+ExecStart=/usr/bin/prx on
+RemainAfterExit=no

systemd/prx-reapply.timer

@@ -0,0 +1,11 @@
+[Unit]
+Description=Periodically re-apply prx proxy routing (handles DHCP/gateway changes)
+
+[Timer]
+Unit=prx-reapply.service
+OnBootSec=1min
+OnUnitActiveSec=5min
+Persistent=false
+
+[Install]
+WantedBy=timers.target