- add rpc node purpose support for general/manual_verify/both
- keep scan, WSS and health checks away from manual_verify nodes
- fallback manual hash verification from general RPC to manual_verify RPC
- add public cashier hash submission path and errno responses
- update tests for RPC selection, failover and manual payment flows
- skip SPA fallback for `/install` and `/install/*` in main server
- keep install wizard accessible only during `RunInstallServer` phase
- prevent post-install access to install UI