fix: preserve static/js directory during OAuth build

Change OAuth asset copying to only remove OAuth-specific files
instead of overwriting entire static directory, preserving
ask-ai.js and other static assets.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.github/workflows/cloudflare-pages.yml

@@ -34,10 +34,16 @@ jobs:
           
       - name: Copy OAuth build to static
         run: |
-          # Remove old assets (following run.zsh pattern)
+          # Remove old OAuth assets only
           rm -rf my-blog/static/assets
-          # Copy all dist files to static
-          cp -rf oauth/dist/* my-blog/static/
+          rm -rf my-blog/static/oauth
+          rm -f my-blog/static/client-metadata.json
+          # Copy OAuth dist files to static (preserving existing files)
+          mkdir -p my-blog/static/assets
+          cp -r oauth/dist/assets/* my-blog/static/assets/
+          cp oauth/dist/client-metadata.json my-blog/static/
+          mkdir -p my-blog/static/oauth
+          cp oauth/dist/index.html my-blog/static/oauth/index.html
           # Copy index.html to oauth-assets.html template
           cp oauth/dist/index.html my-blog/templates/oauth-assets.html