chore: update design template to eve 0.83.0

Summary

The prior upgrade (#2) is merged but targets eve 0.73.0. Upgrade to eve 0.83.0 with compatible, pinned AI SDK dependencies while preserving the read-only runtime and Slack renderer.

CI previously failed because sandbox snapshot preparation requires Vercel project credentials. Keep knowledge verification, tests, typechecking, and compilation in CI, but skip sandbox prewarming there. Production builds still prepare the sandbox normally.

Validation

• Frozen install with strict peer dependencies passed.
• Knowledge verification and all 18 tests passed.
• pnpm type-check and pnpm run info passed with 0 discovery errors or warnings.
• pnpm build --skip-sandbox-prewarm passed locally and the GitHub Actions CI check is green.
• git diff --check passed.

Checklist

• This change was requested or approved by a maintainer
• I ran the relevant checks from CONTRIBUTING.md
• I added tests and documentation where relevant
• I added a changeset if this touches the published eve package
• DCO sign-off passes for every commit (git commit --signoff)