Move the agents platform onto the estate path

[ExtraToast]

Parent

JorisJonkers-dev/deploy-kit#195

What to build

Move the agents platform (agents-api, agents-ui, the agent runtime) onto the estate path:

• First model it: its project file in deploy-kit's vocabulary, including the Kubernetes API access agents-api needs under 0155, which slice 5 brings for machinery.
• Then publish on a release tag, compose, and hand over from fleet-infra.

Acceptance criteria

• The agents project composes with nothing refused.
• A tagged release deploys through the estate path.
• fleet-infra no longer delivers agents.

Blocked by

• Move auth onto the estate path auth-api#80
• Slice 5: render the delivery machinery, Flagger declared as a foundation Application deploy-kit#202