chore: phase 2 and 3 refactors

tests/renderer/navigation/tabPolicy.test.ts

@@ -0,0 +1,25 @@
+import { describe, expect, it } from 'vitest';
+import { getSingletonToolTabSpec, openSingletonToolTab } from '../../../src/renderer/navigation/tabPolicy';
+
+describe('tabPolicy', () => {
+  it('provides canonical singleton tab specs', () => {
+    expect(getSingletonToolTabSpec('settings')).toEqual({ type: 'settings', id: 'settings', isTransient: false });
+    expect(getSingletonToolTabSpec('tags')).toEqual({ type: 'tags', id: 'tags', isTransient: false });
+    expect(getSingletonToolTabSpec('style')).toEqual({ type: 'style', id: 'style', isTransient: false });
+    expect(getSingletonToolTabSpec('documentation')).toEqual({ type: 'documentation', id: 'documentation', isTransient: false });
+    expect(getSingletonToolTabSpec('metadata-diff')).toEqual({ type: 'metadata-diff', id: 'metadata-diff', isTransient: false });
+    expect(getSingletonToolTabSpec('site-validation')).toEqual({ type: 'site-validation', id: 'site-validation', isTransient: false });
+  });
+
+  it('opens singleton tool tabs using canonical tab spec', () => {
+    const openTab = (tab: { type: string; id: string; isTransient: boolean }) => {
+      captured = tab;
+    };
+
+    let captured: { type: string; id: string; isTransient: boolean } | null = null;
+
+    openSingletonToolTab(openTab, 'site-validation');
+
+    expect(captured).toEqual({ type: 'site-validation', id: 'site-validation', isTransient: false });
+  });
+});