Fix docs deploy: copy dotfiles from dist to gh-pages

`cp -r dist/* .` skips `.nojekyll`, which meant underscore-prefixed
directories (_playground/, _framework/, _content/) were still being
stripped by Jekyll on gh-pages.github.io even after adding the
.nojekyll source file. Use `cp -rT dist .` which copies the whole
tree including dotfiles.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: koenbeuk

.github/workflows/docs.yml

@@ -79,8 +79,8 @@ jobs:
             ! -name 'dev' \
             -exec rm -rf {} +
 
-          # Copy new VitePress build output
-          cp -r ../docs/.vitepress/dist/* .
+          # Copy new VitePress build output (dist/. form to include dotfiles like .nojekyll)
+          cp -rT ../docs/.vitepress/dist .
 
           # Configure git
           git config user.name "github-actions[bot]"