docs(frontend): note LazyMap has() LRU caveat + BSL headers on util tests (review feedback)

- LazyMap: document that only get() refreshes LRU recency, not has().
- Add the BSL copyright header to bounded-array.test.ts and lazy-map.test.ts
  for consistency with the other added test files.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: malinskibeniamin

frontend/src/utils/bounded-array.test.ts

@@ -1,3 +1,14 @@
+/**
+ * Copyright 2026 Redpanda Data, Inc.
+ *
+ * Use of this software is governed by the Business Source License
+ * included in the file https://github.com/redpanda-data/redpanda/blob/dev/licenses/bsl.md
+ *
+ * As of the Change Date specified in that file, in accordance with
+ * the Business Source License, use of this software will be governed
+ * by the Apache License, Version 2.0
+ */
+
 import { describe, expect, test } from 'vitest';
 
 import { boundedAppend, pruneMapToKeys, trimToLast } from './bounded-array';

frontend/src/utils/lazy-map.test.ts

@@ -1,3 +1,14 @@
+/**
+ * Copyright 2026 Redpanda Data, Inc.
+ *
+ * Use of this software is governed by the Business Source License
+ * included in the file https://github.com/redpanda-data/redpanda/blob/dev/licenses/bsl.md
+ *
+ * As of the Change Date specified in that file, in accordance with
+ * the Business Source License, use of this software will be governed
+ * by the Apache License, Version 2.0
+ */
+
 import { describe, expect, test } from 'vitest';
 
 import { LazyMap } from './lazy-map';

frontend/src/utils/lazy-map.ts

@@ -17,7 +17,7 @@ export class LazyMap<K, V> extends Map<K, V> {
    * @param defaultCreate factory for missing values.
    * @param maxSize when set, the map behaves as a bounded LRU cache: accessing a key marks it
    *   most-recently-used and inserting beyond `maxSize` evicts the least-recently-used entry.
-   *   Unbounded when omitted (original behaviour).
+   *   Recency is refreshed by `get()` only — `has()` does not bump it. Unbounded when omitted.
    */
   constructor(defaultCreate: (key: K) => V, maxSize?: number) {
     super();