[S7] Create GitHub App listing content

[krakenhavoc]

Description

Content for the GitHub App Marketplace listing.

Required

• App name and description
• Feature list
• Screenshots of check runs, issue notifications, config file
• Permissions justification (why each permission is needed)
• Setup instructions
• Link to documentation
• Support contact

Acceptance Criteria

• Listing content ready for submission
• Screenshots created
• Permissions justified clearly