Pass NATS credentials explicitly: async-nats ignores userinfo in the URL

async_nats::connect() silently drops user:pass embedded in NATS_URL,
so the server rejected every connection with an authorization violation.
Parse the URL and feed credentials through ConnectOptions instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Cargo.lock

@@ -368,6 +368,7 @@ dependencies = [
  "tower-sessions",
  "tracing",
  "tracing-subscriber",
+ "url",
  "uuid",
  "wasm-bindgen",
  "web-sys",