[Question]: imessage ACL 配置

## Question or topic

[What would you like to ask or discuss?]
imessage channel 会有个尴尬的问题，广告商给你发消息，CoPaw 默认配置会导致 CoPaw 也会回复 广告商（存在安全风险）。

## Context

[Relevant setup: CoPaw version, channel, skill, or use case. This helps others answer.]

## Tried so far

[Optional: what you already tried or read (docs, issues, etc.).]

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**Note:** For general questions or ideas, [GitHub Discussions](https://github.com/agentscope-ai/CoPaw/discussions) may get more visibility. Use this template when the answer might lead to a bug report, feature request, or doc change.

The issue names the iMessage channel but no source file, test, or entry point. Start by locating the iMessage configuration and access-control behavior, then clarify the expected handling of messages from unapproved senders and how completion should be verified.

Scritto dal modello di indicizzazione a partire dal testo della issue.