Set default 30s timeout for HTTP RPC client to prevent indefinite hangs

[maradini77]

Summary

Adds a safe default timeout to the HTTP RPC client to avoid requests hanging indefinitely when no context deadline is provided.

Changes

• rpc/http.go:
  • DialHTTP now uses &http.Client{Timeout: 30 * time.Second}.
  • When no custom client is provided, newClientTransportHTTP initializes http.Client with Timeout: 30 * time.Second.

Rationale

• Using http.Client without a timeout is a known anti-pattern and can lead to resource exhaustion/DoS if servers keep connections open without responding.

Backward Compatibility

• Custom clients provided via WithHTTPClient or DialHTTPWithClient are respected and unchanged.