When a Proxmox cluster is discovered, Pulse now includes the user-provided
main host URL as a fallback endpoint. This handles scenarios where Proxmox
reports internal IPs that aren't reachable from Pulse's network (e.g.,
monitoring a remote cluster across different networks).
Previously, if all cluster endpoint IPs were unreachable, the connection
would fail with no fallback. Now the ClusterClient will fall back to the
main host URL, allowing Proxmox to route API calls internally.
Related to #1028
- hashIPToUID: 11 test cases covering IP hashing for rate limiting
(determinism, range bounds, collision detection, boundary values)
- extractNodesFromYAML: 17 test cases covering YAML node list parsing
(map format, list format, mixed types, edge cases)
First test files for config_cmd.go and http_server.go utilities.
