feat: pipeline CI + Docker pour déploiement sur sonic

- Dockerfile multi-stage (node:20 build + nginx:alpine serve)
- nginx.conf SPA avec try_files et gzip
- docker-compose.yml avec labels Registrator/Fabio (SERVICE_80_CHECK_TCP)
- .woodpecker.yml : validate, security-check, build-image, SBOM, write-env,
  test-env, deploy (stop→acme→up), test-deploy, healthcheck
- .gitignore : ajout .env et /.reports/

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

nginx.conf

@@ -0,0 +1,12 @@
+server {
+    listen 80;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    gzip on;
+    gzip_types text/css application/javascript application/json image/svg+xml;
+}