`isMention` is not set on skipped messages, causes `onNewMention` not to fire

[ejtaccendo]

Bug Description

In burst (and queue) concurrency, messages collapsed into context.skipped never have detectMention run on them, leaving isMention undefined. Additionally, onNewMention only fired when the latest message in the burst mentioned the bot — if the mention was in an earlier message (e.g. "@bot help" followed by "please") the handler is silently skipped.

Steps to Reproduce

1. Create a bot with burst mode concurrency
2. Write in new thread quickly enough so both get queued together:

@bot
hello

Expected Behavior

onNewMention is fired

Actual Behavior

onNewMention is not fired

Code Sample

I implemented a fix here, but i cannot create PR since im not collaborator.

https://github.com/thecopy/vercel-chat-sdk/commit/895bde5cdb5d920a18d844c6a49d40a1f8fd5aef

Chat SDK Version

v4.29.0

Node.js Version

v24.14.0

Platform Adapter

Slack

Operating System

macOS

Additional Context

No response