feat: publish standalone worker

Separate worker packaging and service lifecycle from the control plane.

.env.example

@@ -0,0 +1,26 @@
+# Required: create the worker at https://rsmon.ru/settings/workers first.
+RSMON_URL=https://rsmon.ru
+RSMON_TOKEN=replace-with-worker-token
+
+# Local operator console. Both credentials are required while the web UI is on.
+WORKER_HOST=0.0.0.0
+WORKER_PORT=27401
+WORKER_BIND_IP=127.0.0.1
+WORKER_URL=
+WORKER_LOGIN=admin
+WORKER_PASSWORD=replace-with-a-long-random-password
+
+# Persistent web application state.
+RSMON_WEBAPP_DATA_DIR=/var/lib/rsmon-worker/webapp
+
+# Optional Raft worker cluster.
+WORKER_CLUSTER_ENABLED=false
+WORKER_CLUSTER_ID=
+WORKER_CLUSTER_HOST=0.0.0.0
+WORKER_CLUSTER_PORT=37401
+WORKER_CLUSTER_PEERS=
+WORKER_CLUSTER_DATA_DIR=/var/lib/rsmon-worker/cluster
+WORKER_CLUSTER_BOOTSTRAP=false
+
+# Optional update page API endpoint.
+WORKER_RELEASE_URL=