validate manifest rejects the manifest that package produces (requires ai.assets)

[friedrichwilken]

What happens

model-cli package --model test-model --model-path ./test-model --artifact test:v1 --registry oras --registry-url "" --accelerator cpu --non-interactive
model-cli validate manifest --manifest ./test-model/manifest.json --non-interactive

✗ Metadata contract validation FAILED
  - Error: no metadata contract found in annotations. Expected annotation: ai.assets
  - Missing required fields: ai.assets
Error: manifest validation failed: no metadata contract found in annotations. Expected annotation: ai.assets

The ai.assets metadata contract (internal/workflow/metadata_contract.go:92) is only ever written by map / enforce, so the output of the documented package → harden → sign flow never passes validate manifest.

The README lists validate manifest under "Validate – one command family" as "a manifest against the metadata contract (JSON Schema)" with no hint that package output is expected to fail.

Expected

Either

• package writes an ai.assets contract from the information it already has (model name, type, runtime, …), so the packaged manifest is valid, or
• validate manifest treats a missing ai.assets as a warning (fail only with --strict) and the README / --help state that map is the step that adds the contract.