1. Fix missing spaces in cron job wake prompt string concatenation.
Python implicit string concatenation produced:
"...scheduled taskProceed..." and "...conversation.After..."
which sent garbled instructions to the LLM agent, causing unreliable
cron job execution.
2. Replace deprecated datetime.utcnow() with
datetime.now(datetime.timezone.utc) in JWT generation.
utcnow() is deprecated since Python 3.12 and returns naive datetime
which can cause incorrect token expiry on non-UTC systems.
Closes#6103Closes#6165
Co-authored-by: easonysliu <easonysliu@tencent.com>