test(cli-e2e): scaffold.runtime coverage for fresh-ui ai generative-ui renderer

[rickylabs]

Part of #238

Follow-up from slice FB5 / #258.

Scope

Add full scaffold.runtime E2E coverage for the Fresh UI ai collection generative-UI renderer. The smoke should scaffold a project, install the ai Fresh UI collection, feed a nested render_ui payload, and assert the safe renderer DOM path in the generated workspace.

Acceptance

• deno task e2e:cli run scaffold.runtime --cleanup --format pretty covers the render-ui registry item in the ai collection.
• The generated-project assertion includes a nested layout payload containing viz and data blocks.
• The generated-project assertion verifies the renderer fallback for unknown block types or depth overflow without raw HTML.

Notes

The unit regressions for #258 cover the security-critical depth and whitelist guards. This issue tracks the larger generated-project E2E layer only.