backend: add strong typing and tests for /health endpoint

[ShantKhatri]

Summary

Add explicit return payload typing for the existing /health endpoint in apps/backend/src/app.ts and add a vitest test to lock behavior.

Tasks

• in apps/backend/src/app.ts, update /health route to return { status: 'ok' } and annotate with TypeScript type.
• create apps/backend/src/__tests__/app.test.ts or similar and assert GET /health returns 200 and correct body.
• run pnpm --filter @devcard/backend test.

Acceptance Criteria

• /health route is typed and still returns 200.
• automated test passes.

Why this is good first issue

Low risk, easy integration point, adds test coverage for existing behavior.

[nazneen-p1]

Hi @ShantKhatri

I would like to work on this issue under GSSoC'26.

I have experience with JavaScript/TypeScript and backend basics, and I will update the /health endpoint with proper typing and add a test to ensure it returns the expected response.

Please assign this issue to me.

[ShantKhatri]

Hi @ShantKhatri

I would like to work on this issue under GSSoC'26.

I have experience with JavaScript/TypeScript and backend basics, and I will update the /health endpoint with proper typing and add a test to ensure it returns the expected response.

Please assign this issue to me.

Warm Welcome. Assigning.

[nazneen-p1]

Hi @ShantKhatri,

I have completed the implementation and all tests are passing locally.

The Vercel check seems to require authorization, so it might be failing due to permission.

Please review the PR. Thank you!

[nazneen-p1]

Hi @ShantKhatri,

Just a gentle follow-up on this PR. I have completed the implementation and all tests are passing locally.

Please let me know if any changes are needed from my side. Looking forward to your review.

Thank you!

[ShantKhatri]

@nazneen-p1 , we are expecting PR for this by EOD, as per rules, will reassign the issue.