Consider requesting "supported features" from backend to enable/disable/show/hide features

As more features are added, and more users linger on old versions, we lock ourselves in to supporting features we may deem unsuitable or no longer supported.

By having the plugin query for supported features before presenting them, we can avoid legacy support situations. Or even temporarily turn off features while maintenance or backend changes occur. Or add new features/change capabilities that are limited to Teams/Enterprise.

This is similar to how MCP can update its tools at runtime.

How this works for, how it is presented and how we refresh availability will require design and considerations.

> TODO: Decide if we want to introduce a "supported features" endpoint in the backend that permits/prevents features being enabled for users (so we can enable (or disable) these at some future point?)

Open a separate issue for discussion please

_Originally posted by @joepavitt in https://github.com/FlowFuse/nr-assistant/issues/56#issuecomment-2979622864_