Add `app/cli/doctor` diagnostics command

[usmanimamu17-create]

Problem

No one-shot diagnostic.

Why

Triage speed.

Outcome

python -m app.cli.doctor [--json] prints Postgres pool, Redis latency, last SLA compute, last webhook, last audit entry, worker count.

Acceptance

• Exit 0 on healthy

Files

• app/cli/doctor.py (NEW)

[Ssoleed]

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

Hi maintainer, please let me handle this issue efficiently

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[Favourof]

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

I would like to work on this issue.

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[Nwapu-TrustJah]

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

Hi Maintainer, I’d like to take on this issue!
Having a single doctor command makes operational triage and environment checks drastically faster during debugging and deployments.
My execution plan:
CLI Command Setup (app/cli/doctor.py):
Implement the doctor CLI entrypoint supporting both default human-readable terminal output and a structured --json flag.
Diagnostic Metric Checks:
Postgres Pool: Query active pool status/connection health.
Redis Latency: Ping Redis and measure ping latency in milliseconds.
System Signals: Query timestamp of last SLA computation, last webhook execution, and last audit log entry.
Worker Capacity: Inspect active worker counts across the background pool.
Exit Codes & Verification:
Return exit 0 when all service health checks pass, and appropriate non-zero exit codes when critical diagnostics fail.
Add tests verifying both --json output structure and standard CLI exit codes under mock healthy/unhealthy conditions.
Could you please assign this issue to me so I can open a PR?

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[Max347bot]

@Max347bot has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello maintainer please I will like to work on this issue

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[Michealshodipo56]

@Michealshodipo56 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi, kindly assign me to this issue

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[drips-wave]

Congratulations, @Max347bot! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

🧑‍💻 @Max347bot: 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.

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