test: Set up frontend test harness (Vitest) and add first hook tests

[aguilar1x]

Summary

apps/web-app currently has no test infrastructure at all — there is no test script in package.json and not a single *.test.* / *.spec.* file across src/. This means every hook and utility (including financial calculations) ships unverified, and contributors have no harness to add regression tests to.

This issue sets up the testing foundation and lands the first few high-value tests.

Scope

1. Add Vitest + React Testing Library (with jsdom) to apps/web-app, wired into the Turborepo test pipeline.
2. Add a test (and test:watch) script to apps/web-app/package.json.
3. Write the first unit tests for critical, pure-ish logic:
   • apps/web-app/src/features/borrowing/hooks/useHealthFactor.ts — health-factor math
   • apps/web-app/src/lib/utils.ts — cn() and any pure helpers
   • One more hook/util of the contributor's choice with clear input/output

Acceptance criteria

• npm run test (and the Turbo test task) runs Vitest in apps/web-app and passes
• Vitest + RTL + jsdom configured (vitest.config.ts, setup file)
• At least 3 meaningful tests covering real behavior (not just "renders without crashing")
• CI-friendly: tests run headless and deterministically
• Short note in the README on how to run tests

Notes

Keep the first PR focused on the harness + a small set of exemplary tests so future contributors have a clear pattern to copy. Broad coverage of all 90+ components is explicitly out of scope here.

[ezehalexa]

@ezehalexa has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I'd like to work on this issue! because I am very conversant with solving problems like this!

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[Menjay7]

Hi! I came across this issue and would love to work on it. I have experience with similar tasks and I'm confident I can investigate, implement a clean solution, and thoroughly test it before submitting a PR. If the issue is still open, I would appreciate it if you could assign it to me. Thank you!

[Abdulmajeed82]

@Abdulmajeed82 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue pls..

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[agnesnaomiolim-cloud]

@agnesnaomiolim-cloud has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue.

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[Caneryy]

@Caneryy has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, can I work on this issue?

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[drips-wave]

Congratulations, @CodeNinjaStephen! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @CodeNinjaStephen: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

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