fix: replace print() with logging across harness package (#1282)

Replace all bare print() calls with proper logging using Python's
standard logging module across the deerflow harness package.

Changes across 8 files (16 print statements replaced):

- agents/middlewares/clarification_middleware.py: use logger.info/debug
- agents/middlewares/memory_middleware.py: use logger.debug
- agents/middlewares/thread_data_middleware.py: use logger.debug
- agents/middlewares/view_image_middleware.py: use logger.debug
- agents/memory/queue.py: use logger.info/debug/warning/error
- agents/lead_agent/prompt.py: use logger.error
- skills/loader.py: use logger.warning
- skills/parser.py: use logger.error

Each file follows the established codebase convention:
  import logging
  logger = logging.getLogger(__name__)

Log levels chosen based on message semantics:
- debug: routine operational details (directory creation, timer resets)
- info: significant state changes (memory queued, updates processed)
- warning: recoverable issues (config load failures, skipped updates)
- error: unexpected failures (parsing errors, memory update errors)

Note: client.py is intentionally excluded as it uses print() for
CLI output, which is the correct behavior for a command-line client.

Co-authored-by: moose-lab <moose-lab@users.noreply.github.com>

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

@@ -1,5 +1,6 @@
 """Middleware for memory mechanism."""
 
+import logging
 import re
 from typing import Any, override
 
@@ -10,6 +11,8 @@ from langgraph.runtime import Runtime
 from deerflow.agents.memory.queue import get_memory_queue
 from deerflow.config.memory_config import get_memory_config
 
+logger = logging.getLogger(__name__)
+
 
 class MemoryMiddlewareState(AgentState):
     """Compatible with the `ThreadState` schema."""
@@ -122,13 +125,13 @@ class MemoryMiddleware(AgentMiddleware[MemoryMiddlewareState]):
         # Get thread ID from runtime context
         thread_id = runtime.context.get("thread_id") if runtime.context else None
         if not thread_id:
-            print("MemoryMiddleware: No thread_id in context, skipping memory update")
+            logger.debug("No thread_id in context, skipping memory update")
             return None
 
         # Get messages from state
         messages = state.get("messages", [])
         if not messages:
-            print("MemoryMiddleware: No messages in state, skipping memory update")
+            logger.debug("No messages in state, skipping memory update")
             return None
 
         # Filter to only keep user inputs and final assistant responses