fix(functions): forward NPM_AUTH_TOKEN to deploy bundler container

The Docker bundler for `functions deploy` only passes
`NPM_CONFIG_REGISTRY` to the container environment. When `.npmrc`
uses \${NPM_AUTH_TOKEN} for private registry authentication, the
variable is not available inside the container, causing 401 errors.

Forward `NPM_AUTH_TOKEN` from the host environment to the Docker
container, following the same pattern established in PR #3020 for
`NPM_CONFIG_REGISTRY`.

Closes #4927

Author: addniner

internal/functions/deploy/bundle.go

@@ -68,6 +68,9 @@ func (b *dockerBundler) Bundle(ctx context.Context, slug, entrypoint, importMap
 	if custom_registry := os.Getenv("NPM_CONFIG_REGISTRY"); custom_registry != "" {
 		env = append(env, "NPM_CONFIG_REGISTRY="+custom_registry)
 	}
+	if authToken := os.Getenv("NPM_AUTH_TOKEN"); authToken != "" {
+		env = append(env, "NPM_AUTH_TOKEN="+authToken)
+	}
 	// Run bundle
 	if err := utils.DockerRunOnceWithConfig(
 		ctx,