fix(e2e): always clean Playwright browser cache before install

- Add step to delete ~/.cache/ms-playwright before installing browsers
- Guarantees correct browser version for each run
- Prevents mismatched or missing browser binaries (chromium_headless_shell-1208, etc.)
- Should resolve browser not found errors for all browsers

.github/workflows/e2e-tests.yml

@@ -237,6 +237,9 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
+      - name: Clean Playwright browser cache
+        run: rm -rf ~/.cache/ms-playwright
+
       - name: Cache Playwright browsers
         id: playwright-cache
         uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5