fix(netlify): keep auth token out of argv

[WNZhao]

Summary

• authenticate Netlify CLI through its supported NETLIFY_AUTH_TOKEN environment variable
• stop putting the deployment token in process arguments
• add a regression test asserting the secret is absent from argv

Netlify documents NETLIFY_AUTH_TOKEN as the CI authentication path. Keeping the token out of argv avoids exposure through process inspection and captured command errors.

Verification

• pnpm exec vitest run packages/targets/deploy-netlify/src/index.test.ts (8/8)
• pnpm --filter @profullstack/sh1pt-target-deploy-netlify typecheck
• git diff --check