refactor(harness): update modules to use new runtime imports

Update import paths across harness modules:
- agents/lead_agent/prompt.py
- agents/middlewares/ (memory, thread_data, uploads)
- client.py - enhanced with new capabilities
- community/aio_sandbox/
- config/app_config.py - remove deprecated configs
- sandbox/tools.py
- tools/builtins/ (invoke_acp_agent, present_file)
- uploads/manager.py

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/packages/harness/deerflow/tools/builtins/invoke_acp_agent_tool.py

@@ -33,7 +33,7 @@ def _get_work_dir(thread_id: str | None) -> str:
         An absolute physical filesystem path to use as the working directory.
     """
     from deerflow.config.paths import get_paths
-    from deerflow.runtime.user_context import get_effective_user_id
+    from deerflow.runtime.actor_context import get_effective_user_id
 
     paths = get_paths()
     if thread_id:

backend/packages/harness/deerflow/tools/builtins/present_file_tool.py

@@ -8,7 +8,7 @@ from langgraph.typing import ContextT
 
 from deerflow.agents.thread_state import ThreadState
 from deerflow.config.paths import VIRTUAL_PATH_PREFIX, get_paths
-from deerflow.runtime.user_context import get_effective_user_id
+from deerflow.runtime.actor_context import get_effective_user_id
 
 OUTPUTS_VIRTUAL_PREFIX = f"{VIRTUAL_PATH_PREFIX}/outputs"