feat: add schema foundation for document pipeline, agent, and deployment

Add missing topics (librarian, knowledge, collection-management, flow),
pipeline message types (TextDocument, Chunk, Triples, EntityContexts),
service message types (Librarian, Knowledge, Collection, Flow CRUD),
and update AgentResponse for streaming chunk format.

Add RequestResponseSpec enabling flow-scoped request/response calls
(needed by knowledge extraction and agent services). Add requestor
registry to Flow class with proper lifecycle management.

Add end_of_dialog to gateway's isComplete() check for agent streaming.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ts/packages/base/src/spec/index.ts

@@ -2,3 +2,4 @@ export type { Spec } from "./types.js";
 export { ConsumerSpec } from "./consumer-spec.js";
 export { ProducerSpec } from "./producer-spec.js";
 export { ParameterSpec } from "./parameter-spec.js";
+export { RequestResponseSpec } from "./request-response-spec.js";