deploy: add Dockerfile (nginx:alpine), gitignore source/

Prepare for Coolify deployment to ares-docs.kang-kang.com.
Source clone is local-only (gitignored), only index.html ships in image.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,18 @@
+FROM nginx:alpine
+
+COPY index.html /usr/share/nginx/html/index.html
+
+RUN printf 'server {\n\
+    listen 80;\n\
+    server_name _;\n\
+    root /usr/share/nginx/html;\n\
+    index index.html;\n\
+    gzip on;\n\
+    gzip_types text/plain text/css application/javascript text/html application/json;\n\
+    location / {\n\
+        try_files $uri $uri/ /index.html;\n\
+        add_header Cache-Control "public, max-age=3600";\n\
+    }\n\
+}\n' > /etc/nginx/conf.d/default.conf
+
+EXPOSE 80