test and API docs fixing

[yaleman]

Summary

• replace test port probing with listener-based startup using bound TCP and UDP sockets
• add listener-driven server entrypoints for the web API and DNS servers while keeping the config-driven startup paths
• expand OpenAPI and Swagger coverage for record and zone endpoints, including new API docs checks in the test suite
• restore TLS certificate reloads for the pre-bound API listener so runtime cert rotation still works
• simplify and stabilize the shared test setup by binding listeners up front and reusing the assigned addresses