Add a /health endpoint to the Rust Daemon

[CodNoob100]

Context: Currently, the core Rust daemon (
ulld) does not expose a standard health check endpoint. This makes it difficult for tools like Docker or Kubernetes to automatically verify if the service has successfully started and is ready to accept connections.
Task:

1. Open the Rust daemon source file (crates/nulld/src/main.rs).
2. Create a new async function called handle_health that simply returns an HTTP 200 OK with a JSON payload like {"status": "ok"}.
3. Register this new route in the Axum Router block (around line 130) as .route(/health, get(handle_health)).
   Files to Touch: crates/nulld/src/main.rs`nSuccess Criteria: Running cargo run --bin nulld and executing curl http://127.0.0.1:3000/health should return a 200 OK response with the JSON status.