feat(cli): Increase /insight feature exposure via weighted tips

- Add weighted tip system to make certain tips appear more frequently
- Set /insight tip to weight 3 (3x more likely than regular tips)
- Add i18n translations for the new tip across all supported languages
- Add comprehensive unit tests for weighted tip selection

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

packages/cli/src/ui/components/Tips.test.ts

@@ -0,0 +1,62 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi } from 'vitest';
+import { selectWeightedTip } from './Tips.js';
+
+describe('selectWeightedTip', () => {
+  const tips = [
+    { text: 'tip-a', weight: 1 },
+    { text: 'tip-b', weight: 3 },
+    { text: 'tip-c', weight: 1 },
+  ];
+
+  it('returns a valid tip text', () => {
+    const result = selectWeightedTip(tips);
+    expect(['tip-a', 'tip-b', 'tip-c']).toContain(result);
+  });
+
+  it('selects the first tip when random is near zero', () => {
+    vi.spyOn(Math, 'random').mockReturnValue(0);
+    expect(selectWeightedTip(tips)).toBe('tip-a');
+    vi.restoreAllMocks();
+  });
+
+  it('selects the weighted tip when random falls in its range', () => {
+    // Total weight = 5. tip-a covers [0,1), tip-b covers [1,4), tip-c covers [4,5)
+    // Math.random() * 5 = 2.0 falls in tip-b's range
+    vi.spyOn(Math, 'random').mockReturnValue(0.4); // 0.4 * 5 = 2.0
+    expect(selectWeightedTip(tips)).toBe('tip-b');
+    vi.restoreAllMocks();
+  });
+
+  it('selects the last tip when random is near max', () => {
+    vi.spyOn(Math, 'random').mockReturnValue(0.99);
+    expect(selectWeightedTip(tips)).toBe('tip-c');
+    vi.restoreAllMocks();
+  });
+
+  it('respects weight distribution over many samples', () => {
+    const counts: Record<string, number> = {
+      'tip-a': 0,
+      'tip-b': 0,
+      'tip-c': 0,
+    };
+    const iterations = 10000;
+    for (let i = 0; i < iterations; i++) {
+      const result = selectWeightedTip(tips);
+      counts[result]!++;
+    }
+    // tip-b (weight 3) should appear roughly 3x as often as tip-a or tip-c (weight 1)
+    // With 10k iterations, we expect: tip-a ~2000, tip-b ~6000, tip-c ~2000
+    expect(counts['tip-b']!).toBeGreaterThan(counts['tip-a']! * 2);
+    expect(counts['tip-b']!).toBeGreaterThan(counts['tip-c']! * 2);
+  });
+
+  it('handles single tip', () => {
+    expect(selectWeightedTip([{ text: 'only', weight: 1 }])).toBe('only');
+  });
+});