fix: copy custom templates to Jekyll build directory

The competitive-verifier docs action generates markdown to _jekyll but
doesn't automatically copy custom templates. Jekyll needs _includes and
_layouts to be in the source directory to use them.

This explicitly copies our custom templates from .verify-helper/markdown/
to _jekyll/ so Jekyll can find and use our customized document_body.html
with minified code sections.

Author: adamant-pwn

.github/workflows/verify.yml

@@ -176,6 +176,15 @@ jobs:
           verify-result: ${{github.workspace}}/merged-result.json
           destination: _jekyll
           write-summary: true
+      - name: Copy custom templates to Jekyll
+        shell: bash
+        run: |
+          if [ -d ".verify-helper/markdown/_includes" ]; then
+            cp -r .verify-helper/markdown/_includes _jekyll/
+          fi
+          if [ -d ".verify-helper/markdown/_layouts" ]; then
+            cp -r .verify-helper/markdown/_layouts _jekyll/
+          fi
       - name: Inject minified code into documentation
         shell: bash
         run: python3 .verify-helper/scripts/inject_minified_docs.py