Centralize Proxmox node configuration by moving `ProxmoxConfig` from `internal/types/idlewatcher.go` to a new `NodeConfig` struct in `internal/proxmox/node.go`.
- Add `proxmox` field to route; allowing `proxy.app.proxmox` labels and corresponding route file config
- Added `service` optional field to NodeConfig for service identification
- Integrated Proxmox config directly into Route struct with proper validation
- Propagate Proxmox settings to Idlewatcher during route validation
- Updated swagger documentation to reflect schema changes
