fix(uploads): fall back to configurable.thread_id when runtime.context lacks thread_id (#1814)

* fix(uploads): fall back to configurable.thread_id when runtime.context lacks thread_id

runtime.context does not always carry thread_id depending on the
LangGraph invocation path. When absent, uploads_dir resolved to None
and the entire outline/historical-files attachment was silently skipped.

Apply the same fallback pattern already used by ThreadDataMiddleware:
try get_config().configurable.thread_id, with a RuntimeError guard for
test environments where get_config() is called outside a runnable context.

Discovered via live integration testing (curl against local LangGraph).
Unit tests inject uploads_dir directly and would not catch this.

* style: apply ruff format to uploads_middleware.py

backend/packages/harness/deerflow/agents/middlewares/uploads_middleware.py

@@ -147,6 +147,13 @@ class UploadsMiddleware(AgentMiddleware[UploadsMiddlewareState]):
 
         # Resolve uploads directory for existence checks
         thread_id = (runtime.context or {}).get("thread_id")
+        if thread_id is None:
+            try:
+                from langgraph.config import get_config
+
+                thread_id = get_config().get("configurable", {}).get("thread_id")
+            except RuntimeError:
+                pass  # get_config() raises outside a runnable context (e.g. unit tests)
         uploads_dir = self._paths.sandbox_uploads_dir(thread_id) if thread_id else None
 
         # Get newly uploaded files from the current message's additional_kwargs.files