Add init status for ContractsProvider node

Based on discussion with Luca, ContractsProvider needs status like 'isConnecting', 'isSuccess', etc.

Because both signing and query clients are async connecting, so better add status to indicate the progress in later version.

Start by locating the ContractsProvider implementation and tracing how its signing and query clients connect asynchronously. Review the existing client initialization behavior and determine the status states and transitions needed to indicate connection progress; done means the provider exposes those statuses consistently for both clients.

Scritto dal modello di indicizzazione a partire dal testo della issue.