Bug Description

The NO_REPLY silent token is not being filtered from outgoing messages on the webchat channel. It appears as a regular message bubble in the chat UI.

Expected Behavior

Per the agent-loop docs:

NO_REPLY is treated as a silent token and filtered from outgoing payloads.

The token should be silently suppressed and never rendered to the user.

Actual Behavior

NO_REPLY is displayed as a regular assistant message in the webchat interface at 127.0.0.1:18789/chat.

Steps to Reproduce

1. Open the webchat gateway dashboard (/chat?session=agent:main:main)
2. Send a casual message that doesn't require a response (e.g. "thanks")
3. The agent responds with NO_REPLY which is rendered as a visible message bubble

Screenshot

The message appears as a plain text bubble showing "NO_REPLY" from the assistant.

Environment

• OpenClaw version: 2026.2.9
• Channel: webchat (gateway dashboard)
• OS: macOS (Darwin 25.2.0, arm64)
• Node: v25.5.0

Notes

This appears to be webchat-specific — the filtering may work correctly on other channels (Telegram, iMessage, etc.) but the webchat renderer is not checking for the silent token before displaying.