feat: Implement built-in support for Kubernetes resource watching and live sync

[JoseSzycho]

Overview The GraphQL gateway currently supports unary request-response operations (Queries and Mutations) by proxying requests to the Milo APIServer. However, it lacks built-in functionality for Kubernetes resource watching. This prevents clients from implementing a robust "Sync" pattern where they fetch a resource's initial state and stay updated on subsequent changes via a live stream.

Problem Statement

• watch API.

• Lack of Sync Infrastructure: There is no internal mechanism to manage long-lived watch connections or handle the "List then Watch" pattern reliably.

Proposed Solution Implement a generic watching mechanism within the gateway that leverages the 

Implement a generic watching mechanism within the gateway that leverages the @kubernetes/client-node library and exposes events via GraphQL Subscriptions.

[JoseSzycho]

Relates to:

• docs: Add client usage guide and update README with minor formatting and polling interval default. #6 (comment)

@mattdjenkinson FYI