Slack Interactions

Handle Slack interactive component callbacks.

Slack sends interactions as form-encoded data with a 'payload' field containing JSON. We must respond within 3 seconds.

Flow:

1. Parse the payload
2. Immediately return 200 OK (ACK to Slack)
3. Queue Celery task for background processing

Supported interaction types:

• block_actions: User clicks button (e.g., "Edit Summary")
• view_submission: User submits modal (e.g., edited summary)