fix(research): migrate active task owners on rename (#3618)

routes/auth_routes.py

@@ -367,6 +367,20 @@ def setup_auth_routes(auth_manager: AuthManager) -> APIRouter:
         except Exception as e:
             logger.warning("Failed to rename user prefs %s -> %s: %s", old_username, new_username, e)
 
+        # In-flight deep-research tasks live in the process-local
+        # ResearchHandler registry. They are not covered by the persisted JSON
+        # migration above, but the research routes filter and cancel by this
+        # owner field while the job is running. Do this before sweeping
+        # completed JSON files so a job that finishes during the rename saves
+        # with the new owner or is caught by the disk sweep below.
+        try:
+            rh = getattr(request.app.state, "research_handler", None)
+            rename_owner = getattr(rh, "rename_owner", None)
+            if callable(rename_owner):
+                rename_owner(old_username, new_username)
+        except Exception as e:
+            logger.warning("Failed to rename active research tasks %s -> %s: %s", old_username, new_username, e)
+
         # deep_research: each completed report is a standalone JSON file with
         # an `owner` field. research_routes filters by d.get("owner") == user,
         # so a stale owner makes every report invisible to the renamed user.