feat(rs-dapi-client): ban a node per (address, method) instead of for every method #5567

Problem

rs-dapi-client bans a node by address, for every method. Since #3875 an UNIMPLEMENTED answer bans the node and retries elsewhere. But UNIMPLEMENTED is also returned on purpose for endpoints a healthy node does not serve: Drive's broadcast_state_transition, wait_for_state_transition_result and get_consensus_params, any rs-dapi MethodNotFound, and, during a rolling upgrade, a new RPC on nodes still running the previous release. One such call bans an otherwise healthy node for all methods for the whole ban window.

Where

• packages/rs-dapi-client/src/transport/grpc.rs: the Unimplemented arm of the ban decision (TODO(per-method-ban)).
• packages/rs-dapi-client/src/address_list.rs and dapi_client.rs: ban state, live-address selection and ban_info.

Suggested fix

Keep ban windows per (address, method): per-method windows in AddressStatus, get_live_address(method), and the sticky active set filtered by method. Bans that mean the node is unhealthy (transport failures) stay address-wide. This changes the public ban_info shape. Rough size: 300–500 lines plus tests.

Related: #3695 (ban policy per error class), #5561 (the SDK stops sending requests the network cannot serve yet, which removes the rollout case but not the deliberate UNIMPLEMENTED endpoints).

Source: the protocol version 14 feature-gating work for 5.0.0-rc.9, where per-method bans were deferred to 5.1.