Support HITL from Slack

If you've set certain agent tools to require approval before they run, that human-in-the-loop confirmation now also surfaces in Slack when you're having a conversation with an agent there — not just in the web app. If a run pauses for approval, NinjaCat posts an "Approval Required" card in the Slack thread with Allow and Deny buttons — Allow resumes the run, Deny stops it. If a run needs answers to clarifying questions, it posts a single form with all questions at once, including multiple-choice options and an "Other" free-text field, plus Submit and Skip all buttons; leaving a question blank skips it.

Only the person who started the run can act on these prompts, matching how it already works on the web. Replies typed into the thread are handled sensibly: while an approval is waiting, the bot asks you to choose Allow or Deny first; while questions are waiting, your reply is captured as the answer. This requires the NinjaCat Slack app to be installed with Interactivity enabled.