Working sets: Config command + self-describing images fully work in the gateway

[cmrigney]

What I did

• Added working set config commands. See updated doc for details.
• Self-describing images now fully work in the gateway with config and secrets

Related issue

(not mandatory) A picture of a cute animal, if possible in relation to what you did

[bobbyhouse]

question (non-blocking): Are we going to eventually make docker mcp config workingset aware? The strategy for now is to provide workingset specific implementation under docker mcp workingset [new functionality]?

[bobbyhouse]

question (non-blocking): Should we raise an error if the user tries to set a config value that is invalid? We do this with tools, for example

$ docker mcp tools enable blah --server github
tool "blah" not found in server "github"

[cmrigney]

question (non-blocking): Are we going to eventually make docker mcp config workingset aware? The strategy for now is to provide workingset specific implementation under docker mcp workingset [new functionality]?

I'm thinking we probably should, yes. Maybe the same strategy we take for the catalog transition would be good.

question (non-blocking): Should we raise an error if the user tries to set a config value that is invalid? We do this with tools, for example

$ docker mcp tools enable blah --server github
tool "blah" not found in server "github"

I agree, yes. I left a TODO on that. I sort of kicked the can down the road on that, but if you think we should tackle it now, let me know.