chore: update dependencies and configuration

- Added @discordjs/opus and opusscript to package.json and pnpm-lock.yaml.
- Updated pnpm-workspace.yaml to allow builds for @discordjs/opus.
- Imported dotenv in config.ts for environment variable management.
- Created .npmrc to manage npm configurations.

src/config.ts

@@ -1,3 +1,4 @@
+import "dotenv/config";
 import { z } from "zod";
 import { ConfigError } from "./errors.js";