Fix Renderer discovery during App upgrades

[Misiu]

Summary

• use Supervisor discovery only for Renderer transport fields at runtime
• verify API compatibility through the authenticated health endpoint
• accept numeric ports represented as numbers or strings
• add sanitized discovery diagnostics and upgrade regression tests
• release integration 0.6.1

Validation

• 89 Python tests
• Ruff lint and format
• mypy custom_components
• release version validation