Add a Zagros Asset Hub history indexer for the explorer host

The explorer at explorer.pezkuwichain.io needs transfer history for Zagros
Asset Hub. It runs on the explorer host next to its own archive node, so the
manifest points at 127.0.0.1:9955 and the compose file binds everything
locally with memory limits and no published ports.

deploy-vps now ignores these files: a change to the Zagros indexer must not
rebuild or restart the mainnet stack and its bots on the indexer host.

.github/workflows/deploy-vps.yml

@@ -2,6 +2,11 @@ name: Deploy to VPS
 on:
   push:
     branches: [main]
+    # The Zagros history indexer runs on the explorer host, not here.
+    paths-ignore:
+      - zagros-assethub.yaml
+      - docker-compose.zagros.yml
+      - ops/zagros/**
 
 concurrency:
   group: deploy-vps