Update dev.md to create issue with poem in staged mode

- Change workflow task from listing issues to creating an issue
- Task: Create issue with a poem about GitHub Copilot
- Configure safe-outputs.create-issue with title-prefix and max: 1
- Instructions specify using staged mode for preview (🎭 indicator)
- Remove issues:write permission (strict mode doesn't allow write)
- Keep issues:read permission for GitHub toolset
- Recompile dev.lock.yml (424.4 KB)

This addresses the requirement to test MCP gateway with issue creation
in staged mode.

Co-authored-by: pelikhan <[email protected]>

Author: Copilot