chore(create): add test task to packages/create/deno.json (L-3)

[SisyphusZheng]

Problem

packages/create/__tests__/cli.test.ts exists but packages/create/deno.json only defines a run task — no test task.

Suggested fix

"test": "deno test --allow-read --allow-write --allow-run --allow-env __tests__/"

(Overlaps with the M-2 task-alignment issue; can be closed by it.)

Acceptance

• cd packages/create && deno task test runs cli.test.ts

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Source: 2026-07-30 packages/ code review (docs/audit/2026-07-30-packages-code-review.md). Facts verified against source on main @ 0.42.0-alpha.8.

[SisyphusZheng]

Implemented and verified in v0.42.0-alpha.9 (element/app/ui/adapter-vite/create tests green). Closing per the alpha.9 plan.