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>

Dockerfile

@@ -0,0 +1,35 @@
+# syntax=docker/dockerfile:1.7
+
+############################
+# 1) Dependencies
+############################
+FROM node:20-alpine AS deps
+WORKDIR /app
+
+RUN apk add --no-cache libc6-compat
+
+COPY package.json package-lock.json* ./
+RUN npm ci
+
+############################
+# 2) Build stage
+############################
+FROM node:20-alpine AS build
+WORKDIR /app
+
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+
+RUN npm run build
+
+############################
+# 3) Production stage (nginx)
+############################
+FROM nginx:1.27-alpine AS production
+
+COPY docker/nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=build /app/out /usr/share/nginx/html
+
+EXPOSE 8080
+
+CMD ["nginx", "-g", "daemon off;"]