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>

.woodpecker.yml

@@ -0,0 +1,26 @@
+when:
+  branch: main
+  event: [push, manual]
+
+steps:
+  - name: build
+    image: docker:cli
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+    commands:
+      - docker build -t yugioh-frontend:latest .
+
+  - name: deploy
+    image: docker:cli
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+    commands:
+      - docker stop yugioh-frontend || true
+      - docker rm yugioh-frontend || true
+      - docker network create yugioh || true
+      - docker run -d
+          --name yugioh-frontend
+          --restart unless-stopped
+          --network yugioh
+          -p 8041:80
+          yugioh-frontend:latest