[Backend] Add stream metrics endpoint

[ogazboiz]

https://t.me/+DOylgFv1jyJlNzM0

Description

There is no admin endpoint to observe the health and growth of the platform. A GET /admin/metrics endpoint returning aggregate stats (total streams, breakdown by status, total volume streamed) gives operators a quick pulse check and feeds future dashboards or alerting. This is a read-only DB aggregation query making it a well-scoped entry point for new contributors.

Acceptance Criteria

• GET /api/v1/admin/metrics is implemented and registered in the admin router
• Endpoint requires admin auth (existing admin middleware)
• Response body shape:

  {
    "total_streams": 0,
    "active_streams": 0,
    "paused_streams": 0,
    "completed_streams": 0,
    "cancelled_streams": 0,
    "total_volume_streamed": "0"
  }

• total_volume_streamed is the sum of withdrawn_amount across all streams (as a string to avoid JS number precision loss)
• Results are cached for 60 seconds to avoid hammering the DB on repeated polls
• Unit test mocks the repository and asserts the response shape and cache behaviour

Files to Touch

• app/api/routes/v1/admin/metrics.ts — new route handler
• app/api/routes/v1/admin/index.ts — register the route
• app/repositories/stream.repository.ts — add getMetrics() aggregation query
• tests/integration/admin/metrics.test.ts — new test file

[dot-enny]

@dot-enny has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hi i think i can handle this.

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[Babigdk]

@Babigdk has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hi Maintainer,
I’d like to contribute to resolving this issue. I’m a software engineer with strong experience in computer science and believe I can add value here.
Thank you!

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[Vivian-04]

@Vivian-04 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hii Maintainer,
I'd love to get on this, please assign!!

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[davedumto]

@davedumto has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

can I work on this issue?

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