Add Service Groups — a way to manage multiple Services (from the same container/image) as one logical group, with dynamic configuration.

Key needs:

•  Dynamically add/remove services in the group via API

•  Per-service overrides (env vars, command, resources, etc)

•  Group-level management and updates

This would unlock a lot of advanced use cases which may be possible via the Railway API but are inconvenient and subpar from a product experience perspective.