add Docker and CI/CD pipeline with ledo

Configure Next.js static export with nginx serving, Dockerfile
(multi-stage build), docker-compose for prod/dev, Gitea Actions
pipelines for build-on-push and tag-based releases using ledo tool.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/docker-compose.dev.yml

@@ -0,0 +1,17 @@
+version: "3.7"
+services:
+  site:
+    build:
+      context: ../
+      target: build
+    volumes:
+      - "../:/app"
+      - "/app/node_modules"
+      - "/app/.next"
+    ports:
+      - "3000:3000"
+    command: npm run dev
+    environment:
+      - NODE_ENV=development
+    networks:
+      - network-automancer-dev