docs: publish the license pledge and a governance document #394

Why

Self-hosters have watched open core projects move features behind enterprise licenses or relicense. A written pledge removes that fear.

What

• GOVERNANCE.md: who maintains the project, how decisions and releases are made, how security reports are handled
• License pledge: Seamless Auth stays Apache-2.0 with no enterprise edition; SSO, SCIM, MFA, organizations and security features stay in the open source product; any managed offering sells hosting and support, never features
• Linked from every repo's README and the docs site

Where

• GOVERNANCE.md in the org .github repository, so it is the default for every repo
• The pledge in the API README and a docs FAQ entry

Done when

• GOVERNANCE.md states honestly that the project has one maintainer today, and how security reports and releases are handled
• The pledge is in the API README and the docs, and every Seamless repo README links to both
• Published after the docs repository is public (chore: make the docs repository public seamless-auth-docs#112)