[Bug] Redact LINE WORKS user identifiers from chat connector logs

[shaaravraghu]

Description

The chat connector logs raw user identifiers in multiple places, even though the enterprise hardening guide explicitly calls out log sanitization as a high-priority production task. This creates an unnecessary PII leak into centralized logging backends.

Component

• Chat Connector
• Flowise Flow
• Demo MCP Server
• Documentation
• Other

Steps to Reproduce

1. Inspect the /callback handler in chat-connector/app/routes.py.
2. Send a normal text message through the webhook flow.
3. Observe that the logs include the raw userId on receipt, oversize-message warnings, and send confirmation.

Expected Behavior

Logs should avoid printing raw user identifiers. A hashed, truncated, or request-correlated identifier should be used instead.

Actual Behavior

The code logs userId directly:

• Received callback from user: ...
• Message from <user_id> exceeds max length ...
• Sent reply to user <user_id>

Environment

• OS: Any
• Python version: Source analysis
• Docker version: N/A
• Chat platform: LINE WORKS
• Flowise version: N/A

Logs

Relevant code paths:
- chat-connector/app/routes.py:56
- chat-connector/app/routes.py:79
- chat-connector/app/routes.py:107
- docs/enterprise-guide.md:31-34

Additional Context

The repo already documents log sanitization as a P1 recommendation, so there is a clear code/docs mismatch.

Evidence

• chat-connector/app/routes.py
• docs/enterprise-guide.md

Suggested fix

• Introduce a helper that redacts or hashes user identifiers before logging
• Add a request/correlation ID so traces remain useful after redaction
• Consider switching to structured JSON logs for downstream filtering