Add Docker, Woodpecker CI/CD, and cleanup

- Add Dockerfile and .dockerignore for containerisation
- Add .woodpecker.yml pipeline (build + deploy to yugioh network on .101)
- Add .gitignore to stop tracking .env; replace with .env.example
- Add npm start script
- Fix index.js: move versionRoutes require before listen, add /health endpoint
- Fix git remote push URLs (were pointing at Dashboard repo)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,7 @@
+FROM node:20-alpine
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci --omit=dev
+COPY src/ ./src/
+EXPOSE 3000
+CMD ["node", "src/index.js"]