fix: add nginx config for Jekyll clean URLs

Configure nginx to try .html extension for clean URLs like /music/shadow

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

Dockerfile

@@ -27,6 +27,9 @@ RUN bundle exec jekyll build
 # Production stage
 FROM nginx:alpine
 
+# Copy custom nginx configuration
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+
 # Copy built site from builder
 COPY --from=builder /app/_site /usr/share/nginx/html