Feature request: ackReactionScope option to exclude bot messages

Summary

Add an option to filter auto-reactions (ackReaction) to exclude bot/agent messages, reacting only to human messages.

Use Case

In multi-agent setups where several OpenClaw agents share Slack channels, the current ackReactionScope options (group-mentions, group-all, direct, all) cause agents to react with 👀 to each other's messages, creating noise.

We want agents to acknowledge human messages with reactions while ignoring other agents' messages.

Current Behavior

ackReactionScope: "all" reacts to every message including bot messages.

Proposed Solution

Add one of:

1. New scope value: "humans-only" or "exclude-bots"
2. New boolean: ackBotMessages: false (default true for backward compatibility)
3. Extend scope syntax: "all-humans", "group-all-humans"

Environment

• OpenClaw version: 2026.2.12
• Channel: Slack
• Config location: ~/.openclaw/openclaw.json

Current Config

{
  "messages": {
    "ackReaction": "eyes",
    "ackReactionScope": "all"
  }
}

Workarounds Considered

• allowBots: false — But this ignores bot messages entirely, breaking agent coordination
• ackReactionScope: "group-mentions" — Reduces noise but doesn't solve human-only requirement
• Remove ackReaction — Loses useful acknowledgment for humans