Launch Buildly open source hackathon kit

[glind]

Summary

Use the new hackathon kit to prepare the first Buildly open source hackathon run.

Organizer Tasks

• Review the hackathon wiki pages in docs/wiki/.
• Confirm the event theme and challenge tracks.
• Verify Buildly, bb-agent MCP, and AI developer tool setup instructions.
• Publish participant onboarding links.
• Confirm judging rubric and demo timing.
• Create sample team issues using the product brief and AI/MCP task templates.

Acceptance Criteria

• Event organizers have approved the playbook.
• Required links and tool setup notes are current.
• Teams can use the README as the entry point.
• The first event has a clear kickoff, lab, and demo-day flow.

Related

• Draft PR: Add hackathon starter kit #1