Function build_config_sync_runtime_with_runtime_id 

pub fn build_config_sync_runtime_with_runtime_id(
    config: &ConfigSyncConfig,
    namespace: &str,
    runtime_id: impl Into<String>,
) -> Result<ConfigSyncRuntime>

Builds a namespaced config-sync runtime with an explicit runtime ID.

Products normally use build_config_sync_runtime. This variant is useful when the product already has a stable process identity or when tests need deterministic self-origin filtering.