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/flow/src/gateway/dispatch/manager.ts

@@ -152,6 +152,7 @@ export class DispatcherManager {
       !!res.endOfSession ||
       !!res.end_of_stream ||
       !!res.end_of_session ||
+      !!res.end_of_dialog ||
       !!res.eos ||
       // error responses are always final
       !!res.error