[P2] Publish beta/GA release criteria, compatibility matrix, and support policy

[Gsbreddy]

Summary

The project has a strong changelog and a solid architecture narrative, but there is no explicit release-readiness framework describing what beta or GA actually mean.

Problem

Release maturity is implied through versions and shipped features instead of an explicit bar for installability, compatibility, upgrades, and operational support.

Why this matters

Users and maintainers cannot easily tell when Asya is ready for broader adoption, or which guarantees come with each stage.

Scope

• publish beta entrance criteria
• publish GA entrance criteria
• define supported deployment/transport matrix
• define compatibility expectations across charts, gateway, operator, and sidecar
• define upgrade and rollback confidence expectations
• define known limitations and support boundaries

Acceptance criteria

• beta and GA have explicit published criteria
• supported install profiles and transport combinations are documented
• compatibility and upgrade expectations are visible to adopters

Evidence

• CHANGELOG.md
• docs/setup/README.md
• gaps identified during community install testing and docs review