0645 — Binding is a handle under the group; client lists are bare plurals

Context. SystemHandle.ListBindingDeclarations was the one binding read: a fleet-wide listing with no way to ask for one group’s effective set. Every binding_config and binding_config_log row is keyed by consumer_group_id inside one topic’s tables, so the resource’s identity is (topic, group), the same as the group’s. The client layer had also drifted into two list spellings: bare plurals beside their singular constructors (Topics/Topic, Groups/Group, Alerts/Alert) and List* on four leaf reads (ListWorkers, ListMessages, ListKeyMessages, ListBindingDeclarations).

Decision. The read-model is consume.Binding (was BindingDeclaration), the handle BindingHandle, reached as client.Topic(t).Group(g).Binding() with no arguments — the group is the identity, as client.System() is nameless. Get is the comma-ok read: nil when the topic or group is absent, or when the group never installed a set and reads the whole topic. The fleet listing stays on the system as System().Bindings(ctx). Underneath: MessageAdmin.GetBinding resolves names like GetGroup; ConsumeController.GetBinding picks the newest installed row from the datastore’s per-group ListGroupBindingConfigLog, a Wrap pair over the query the declare transaction already ran. Only Get ships; Waiting, Log, and Matches sit in ROADMAP Later, and Declare/Clear stay out per [0511].

Client lists are bare plurals, never List*: Workers, Messages, KeyMessages rename in the same change. List<Noun>s/Get<Noun> remain the admin, controller, and datastore spelling.

The <Noun>Declaration suffix row leaves CONVENTIONS ## Naming and the [0644] role list: BindingDeclaration was its only user, and the value a caller reads is the binding itself. The datastore’s log-row names keep the declaration word (BindingConfigLogRow, DeclareBindings, NewestInstalledDeclaration), which is what those rows are. The stale BindingLog* datastore names became BindingConfigLog*, matching the table since [0611].

The CLI nests the read under the group like group config: vulkan group binding list (moved from alert bindings) and vulkan group binding get <topic> <group>.

Consequences. Compile-time breaking renames on the client, JSON unchanged. ConsumerConfig.Bindings keeps its name; the field is the declaration input, the handle is the stored result. Amends [0644]‘s role list and supersedes [0625]‘s List<Child> clause outright.

Rejected: a top-level binding CLI noun (top-level nouns are client- or system-level handles); moving the list to Client beside Topics (deferred, not refused); Declare/Clear on the handle.