First four independent files for @ commands. (#205)

packages/cli/src/ui/utils/commandUtils.ts

@@ -0,0 +1,17 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * Checks if a query string potentially represents an '@' command.
+ * It triggers if the query starts with '@' or contains '@' preceded by whitespace
+ * and followed by a non-whitespace character.
+ *
+ * @param query The input query string.
+ * @returns True if the query looks like an '@' command, false otherwise.
+ */
+export const isPotentiallyAtCommand = (query: string): boolean =>
+  // Check if starts with @ OR has a space, then @, then a non-space character.
+  query.startsWith('@') || /\s@\S/.test(query);