ci: clear npm cache on Windows to prevent corruption

Windows GitHub Actions runners have a known issue with npm cache
corruption that causes 'ECOMPROMISED: Lock compromised' errors.

This adds a cache clean step before tests on Windows to work around
the issue. The step uses continue-on-error to ensure it doesn't fail
if the cache is already clean.

Author: mldangelo

.github/workflows/test.yml

@@ -76,6 +76,11 @@ jobs:
         with:
           node-version: "24"
 
+      - name: Clear npm cache on Windows
+        if: runner.os == 'Windows'
+        run: npm cache clean --force
+        continue-on-error: true
+
       - uses: astral-sh/setup-uv@v7
         with:
           enable-cache: true