* chore: bump version to 0.6.0 and remove deprecated env var aliases
BREAKING CHANGES:
- POTATOMESH_INSTANCE removed — use INSTANCE_DOMAIN
- PROVIDER removed — use PROTOCOL
- MESH_SERIAL removed — use CONNECTION
- PORT config alias removed — use CONNECTION
The _ConfigModule proxy class (which kept PROTOCOL/PROVIDER and
CONNECTION/PORT in sync) is deleted. docker-compose.yml now defaults
INSTANCE_DOMAIN to http://web:41447 so deployments without an explicit
value continue to work.
* tests: run black
* address review comments
l5y