Function spawn_blocking 

pub async fn spawn_blocking<F, T>(f: F) -> Result<T, LiteError>
where
    F: FnOnce() -> T + Send + 'static,
    T: Send + 'static,

Run a blocking closure off the async runtime.

• Native: tokio::task::spawn_blocking — moves closure to the blocking pool.
• WASM: Runs synchronously (WASM has no blocking pool; callers must ensure the closure is fast or use the async StorageEngine path).