Add IrmaClient::health() wrapper for the /health endpoint

[rubenhensen]

irmago v0.15.0 added a `/health` endpoint that returns 200 when the server is ready to serve sessions. Useful for liveness/readiness checks in deployments that consume irmars (e.g. checking the IRMA server is reachable before starting a session).

Proposed surface

Add `IrmaClient::health(&self) -> Result<(), Error>` that issues `GET {base}/health` and returns `Ok(())` on 2xx, mapped `Error::NetworkError` otherwise.

Implementation is a one-liner; the value is having it on the typed client surface so downstream consumers don't reach for `reqwest` directly.

References

• irmago v0.15.0 release

[dobby-coder]

/dobby fix — add an IrmaClient::health() wrapper that calls the IRMA server /health endpoint, mirroring the existing client method style. Include a test and open a draft PR.

[dobby-coder]

PR #15 (feat/irmaclient-health) looks good to me! The health() method follows the same pattern as cancel() and status() — clean GET request, proper error mapping, and the integration test mirrors test_cancel.rs with the RUN_INTEGRATION_TESTS gate. cargo fmt, clippy, and cargo test all pass with no issues.

Left as a draft since fully exercising /health requires the irma binary locally — that's the right call. No rule violations found.