Add scoped identity listings and backend inventory

internal/configuration/load.go

@@ -124,6 +124,7 @@ type loaded struct {
 	prompts         map[string]*promptEntry
 	registry        *backend.Registry
 	indexedProfiles map[string]domain.ExecutionProfile
+	backendIDs      []string
 	profileIDs      []string
 	promptIDs       []domain.PromptIdentity
 }
@@ -260,6 +261,7 @@ func load(main configkit.Input, underlays []configkit.Underlay) (*loaded, error)
 	if err := state.buildExecutionProfiles(); err != nil {
 		return nil, fmt.Errorf("load configuration: %w", err)
 	}
+	state.backendIDs = sortedKeys(indexedBackends(&result.Config))
 	state.profileIDs = sortedKeys(state.indexedProfiles)
 	for _, id := range sortedKeys(state.prompts) {
 		state.promptIDs = append(state.promptIDs, domain.PromptIdentity{ID: id, Version: stringPointerValue(state.prompts[id].definition.Version)})