#643 model delete --json output shape doesn't match the documented {deleted, modelId, modelName, artifactsDeleted}

Summary

The documented output shape for swamp model delete --json does not match what the CLI actually returns.

The reference docs (.claude/skills/swamp/references/model/guide.md, "Delete a Model") document this shape:

{
  "deleted": true,
  "modelId": "<uuid>",
  "modelName": "<name>",
  "artifactsDeleted": { "outputs": 5, "dataItems": 3 }
}

The CLI actually returns:

{
  "deleted": {
    "id": "<uuid>",
    "name": "<name>",
    "type": "<model-type>",
    "inputPath": "<repo>/models/<type>/<uuid>.yaml"
  },
  "resourceDeleted": false,
  "outputsDeleted": 0,
  "evaluatedInputDeleted": false,
  "dataDeleted": false
}

So: deleted is an object, not a boolean; there is no modelId / modelName / artifactsDeleted; and the artifact counts are spread across resourceDeleted / outputsDeleted / evaluatedInputDeleted / dataDeleted.

Environment

• swamp 20260611.205205.0-sha.ad439a70 (latest; swamp update --check reports up_to_date)
• macOS, arm64
• Reproduced with a freshly created and deleted model (behavior is model-type-independent).

Steps to reproduce

swamp model create <type> delete-shape-test --json
swamp model delete delete-shape-test --json

Impact

Agents and scripts following the documented shape parse .deleted == true / .modelName and get nulls, making a successful delete look like a failure and requiring a follow-up model search to confirm deletion.

Suggested fix

Either update the reference doc to the actual shape, or (better for stability) emit the documented shape: a boolean deleted, the model name/id at top level, and an artifactsDeleted rollup.