Simple webhook to catch Slack member_joined_channel events.

1. Go to api.slack.com/apps and create an app
2. Enable Event Subscriptions and paste this val's URL
3. Subscribe to member_joined_channel under bot events
4. Install the app to your workspace

• Handles Slack's URL verification challenge automatically
• Stores every member_joined_channel event to SQLite
• Dashboard shows captured events at the val's URL

Each event stores:

• user_id - The Slack user who joined
• channel_id - The channel they joined
• team_id - The workspace
• raw_event - Full event payload