[S4] Add a GET /health endpoint to the NestJS server

[Akshola00]

Description

The frontend has no way to distinguish between "server is down" and "this specific request failed". A simple health endpoint lets the frontend (or a future monitoring tool) check server availability and show a useful banner rather than confusing 5xx errors on every page.

Deliverables

• Add a GET /health route to app.controller.ts (or a new HealthController)
• Response: { status: 'ok', timestamp: new Date().toISOString() }
• HTTP 200 always (no auth required — health is public)
• npm run build passes in nevo_server/
• npm run lint passes in nevo_server/

Notes

No new packages needed — plain NestJS controller method is sufficient. Do not add @nestjs/terminus unless the task explicitly requires dependency health checks.

[Ayilojay]

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

Hi Maintainer! I would like to work on this issue

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[Ayilojay]

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

Hi Maintainer! I would like to work on this issue

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[Kezlarry]

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

Please maintainer assign this issue to me I'm confident that I can solve it my eta is 4 hours

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[zeemscript]

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

Hello @maintainer, I’ve gone through the requirements and I’m confident I can implement a proper solution that matches the acceptance criteria. Kindly assign this issue to me. And I will deliver at the shortest possible time.

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