starknet_os_runner: add health and ready endpoints

[avi-starkware]

Add standard Kubernetes-style health check endpoints:

• GET /health: liveness probe, always returns 200 OK
• GET /ready: readiness probe, returns 200 OK when ready

[reviewable-StarkWare]

This change is 

[github-actions]

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• Started at 2026-01-27T11:13:46Z

[AvivYossef-starkware]

@AvivYossef-starkware reviewed 3 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @noaov1 and @Yoni-Starkware).

---

crates/starknet_os_runner/src/server/http_server.rs line 198 at r1 (raw file):

        ],
    }
}

plz document, and consider splitting it into 2 separate checks, I think it would be clearer

Suggestion:

/// Verify:
/// 1. RPC url is reachable.
/// 2. RPC chain id is the same as the expected chain id.
async fn check_rpc_checks(prover: &VirtualSnosProver) -> Vec<CheckStatus> {
    let client = JsonRpcClient::new(HttpTransport::new(prover.rpc_url().clone()));
    match client.chain_id().await {
        Ok(chain_id) => {
            // The rpc is reachable.
            // Verify that the chain id is the same as the expected one.
            let availability_check = CheckStatus { name: "rpc_available", ok: true, message: None };
            let expected = prover.chain_id().as_hex().to_lowercase();
            let actual = chain_id.to_hex_string().to_lowercase();
            let chain_id_check = if actual == expected {
                CheckStatus { name: "rpc_chain_id", ok: true, message: None }
            } else {
                CheckStatus {
                    name: "rpc_chain_id",
                    ok: false,
                    message: Some(format!(
                        "RPC chain id {actual} does not match expected {expected}"
                    )),
                }
            };
            vec![availability_check, chain_id_check]
        }
        // If the RPC is unavailable, we skip the chain id check.
        Err(err) => vec![
            CheckStatus {
                name: "rpc_available",
                ok: false,
                message: Some(format!("RPC unavailable: {err}")),
            },
            CheckStatus {
                name: "rpc_chain_id",
                ok: false,
                message: Some(format!("RPC chain id check skipped: RPC unavailable: {err}")),
            },
        ],
    }
}