Remove Compose authoring from Core #987

Parent

Spec: 1.0 tree cleanup and release contracts

What to build

Cloud-authored Deploy Intent is the sole authored model. Remove Compose file and Go-helper input, x-* interpretation, and the CLI workflow that feeds them while retaining Cloud's Deploy path.

Acceptance criteria

• Cloud can still submit and execute a Deploy Intent through the existing SDK/RPC path.
• Compose input and its helper are no longer accepted or built; no obsolete Compose tests remain.

Blocked by

None — can start immediately