Auto-create GitHub issues from backlog / roadmap posts

Problem

Creating Hollahoop backlog or roadmap posts does not open GitHub issues. Agents and eng still need a second manual step. Link-to-existing-issue + auto-ship on close exist, but post → issue creation does not.

Goal

When a post is created (or moved) into a configured board/status (e.g. Backlog, Roadmap, Planned), Hollahoop optionally creates a GitHub issue in a linked repo and stores the github_post_links row automatically.

Acceptance criteria

• Per-project (or per-board) setting: target repo, label(s), issue template, which statuses trigger create
• On create/move into trigger status: open GitHub issue with title + body from the post; link it back
• Idempotent: never open a second issue if one is already linked
• Toggle default off so existing projects are unchanged
• Agents/MCP: create_post with create_github_issue: true (or project default) should return the issue URL
• Failures surface in the post UI; retry safe

Why

Bizni (and other LAFU products) plan work in Hollahoop. Without auto-issues, Cursor/other agents cannot pick up engineering work from GitHub alone. This closes the loop for multi-agent workflows.

Out of scope

Full body sync both ways; comment mirroring.