Function run_server 

pub fn run_server(args: Args) -> Result<(), ServerError>

Synchronous server entrypoint. Builds a multi-threaded tokio runtime, installs the global tracing subscriber, and runs the HTTP server until SIGINT/SIGTERM.

Lifetime requirement

The caller MUST call init_telemetry BEFORE this function and hold the returned TelemetryGuard for the entire process lifetime.

Errors

Returns ServerError if runtime construction fails or the HTTP server fails.