feat(help): add "Mark Active" button to inactivity warning

[SleepyStack]

Fixes #1140

Overview

Added a "Mark Active" button to help threads flagged for inactivity.

Instead of a "Dismiss" button, I put "Mark Active" because it better reflects the user's intent to keep the thread open. When clicked, the bot unarchives the thread and deletes the inactivity warning to keep the history clean.

Changes

• HelpThreadAutoArchiver.java: Added the button to the inactivity message and updated the embed text to tell users to click it to reopen the thread.
• HelpThreadCreatedListener.java:
  • Created a small hook in onButtonClick using a new thread-inactivity namespace.
  • This ensures the reactivation logic stays isolated from the existing ChatGPT dismiss button.
  • Added handleMarkActiveInteraction to unarchive the thread and delete the bot's warning message.

Why this approach?

A button is more reliable than a message listener since it bypasses the 14-day deletion limit and doesn't require extra database tracking. It's a simple fix that doesn't mess with the existing thread logic.

[CLAassistant]

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