Add Windows to CI test matrix

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: richardkmichael

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [macos-latest, ubuntu-latest]
+        os: [macos-latest, ubuntu-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 15
 
@@ -41,7 +41,7 @@ jobs:
         id: playwright-cache
         uses: actions/cache@v4
         with:
-          path: ${{ matrix.os == 'macos-latest' && '~/Library/Caches/ms-playwright' || '~/.cache/ms-playwright' }}
+          path: ${{ matrix.os == 'macos-latest' && '~/Library/Caches/ms-playwright' || (matrix.os == 'windows-latest' && '~/AppData/Local/ms-playwright' || '~/.cache/ms-playwright') }}
           key: playwright-${{ matrix.os }}-${{ hashFiles('package-lock.json') }}
 
       - name: Install Playwright browsers

playwright.config.js

@@ -18,7 +18,7 @@ export default defineConfig({
   expect: {
     toHaveScreenshot: {
       // 2% threshold: tolerates system font differences across platforms
-      // (macOS uses San Francisco, Linux uses Noto Sans/DejaVu)
+      // (macOS: San Francisco, Linux: Noto Sans/DejaVu, Windows: Segoe UI)
       maxDiffPixelRatio: 0.02,
       // Per-pixel threshold: allow slight color variance from anti-aliasing
       threshold: 0.2,