[Backend] backend/src/routes/health.routes.ts liveness check does not distinguish 'DB unreachable' from 'indexer lagging' in its response body

[grantfox-oss]

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Why this matters

A separate issue already tracks the hardcoded lag threshold in health.routes.ts. This issue is about the response shape: if both a database outage and a lagging indexer report the same generic unhealthy status with no reason or component field, an on-call engineer looking at monitoring dashboards can't tell at a glance which subsystem needs attention without digging into logs.

Acceptance criteria

• Add a checks object to the health response breaking down individual subsystem status (database, redis, indexer lag, soroban RPC)
• Keep the top-level status field for simple uptime monitors that only check one field
• Update docs/api OpenAPI/Postman references to reflect the new shape

Files to touch

• backend/src/routes/health.routes.ts

Out of scope

• Changing the lag threshold value (tracked separately)
• Adding a full status-page integration

[Hollujay]

@Hollujay has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Kindly assign to me.

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[david87131]

@david87131 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi maintainer Let me work on this issue
I'll definitely give you quick response

ℹ️ Repo Maintainers: To accept this application, review their application or assign @david87131 to this issue.

[drips-wave]

Congratulations, @david87131! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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