Update Schemathesis API Testing to wait for health endpoint

[davideme]

Update the Schemathesis API Testing configuration to ensure it waits for the /health endpoint to report healthy before running tests.

Requirements:

• The CI pipeline (or any local test runner) should poll the /health endpoint and start Schemathesis-based tests only once it returns 200 OK.
• Add logic in the test scripts or CI configuration to wait/retry for the health endpoint to be healthy (with timeout and error handling).
• If this is already implemented, document where and how it is handled.
• Update documentation to describe this health check mechanism for contributors.

Motivation:

• Prevents race conditions where API tests run before the server is fully started, reducing spurious test failures.

Notes:

• Check both CI config and local developer scripts for Schemathesis integration.
• If the health check is already in place, reference the relevant commit or documentation and close this issue as not needed.