fix(middleware): fall back to configurable thread_id in MemoryMiddleware (#1425)

[ggnnggez]

Summary

Fix issue #1425

Fix MemoryMiddleware.after_agent() so memory writes are not skipped on LangGraph
runs.wait calls when runtime.context does not contain thread_id.

What changed

• keep reading thread_id from runtime.context first
• fall back to config.configurable.thread_id when it is missing

Why

On direct LangGraph API POST /threads/{thread_id}/runs/wait calls, runtime.context may
not include thread_id. In that case, the previous implementation skipped memory updates
before enqueue.

Verification

• reproduced the issue locally with make dev
• confirmed the pre-fix behavior on POST /threads/{thread_id}/runs/wait:
  • MemoryMiddleware: No thread_id in context, skipping memory update
• applied the fallback to config.configurable.thread_id
• confirmed the post-fix behavior:
  • memory update was enqueued from MemoryMiddleware.after_agent()
  • the queued write job executed successfully
  • backend/.deer-flow/memory.json was written successfully

[CLAassistant]

All committers have signed the CLA.

[Copilot]

Pull request overview

Fixes DeerFlow’s MemoryMiddleware.after_agent() so memory updates are still enqueued for direct LangGraph runs.wait calls where runtime.context may not include thread_id, by falling back to LangGraph config’s configurable.thread_id.

Changes:

• Import LangGraph get_config and use it as a fallback source for thread_id when runtime.context lacks it.
• Keep the existing behavior of preferring runtime.context["thread_id"] when present.

[Copilot]

The skip log message is now potentially misleading: if thread_id is missing in both runtime.context and config.configurable, it still says "No thread_id in context". Consider updating the message to mention both sources (context and config.configurable) to make debugging runs.wait vs other call paths clearer.

Suggested change

	print("MemoryMiddleware: No thread_id in context, skipping memory update")
	print(
	"MemoryMiddleware: No thread_id found in runtime context or config.configurable, "
	"skipping memory update"
	)