Maintainer guide

• Maintainer workflow: source owners, checks and local integration.
• Naming rules: product, Plugin and package identities.
• Adapt external ideas: attribution, licensing and adaptation.
• Release branch policy: stable, prerelease and authorization.
• Publish native packages: GitHub, npm, PyPI and Cargo release workflow.

Start source changes with the development guide. Older quality reports and design records remain in historical material.