Add Docker, Woodpecker CI/CD, and dev proxy setup

- Add multi-stage Dockerfile (Vite build → Nginx serve)
- Add nginx.conf: serves SPA, proxies /api/ to yugioh-api:3000
- Add .woodpecker.yml pipeline (build + deploy on yugioh network, port 8041)
- Add .dockerignore
- Add .env.example with VITE_API_URL
- Update .gitignore to exclude .env files
- Update vite.config.js: proxy /api to backend in dev via VITE_API_URL
- Fix git remote push URLs (were pointing at Dashboard repo)

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

.dockerignore

@@ -0,0 +1,5 @@
+node_modules
+dist
+.env
+.env.local
+.git