feat: Add Docker infrastructure and Gitea CI/CD pipeline

- Add Dockerfiles for server, client, and admin services
- Create docker-compose.yml for orchestration
- Add Gitea Actions workflow for automated build/deploy
- Configure conditional builds based on directory changes
- Use gitea.interno.com registry for image storage

🤖 Generated with [Claude Code](https://claude.ai/code)

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

server/Dockerfile

@@ -0,0 +1,27 @@
+# Server Dockerfile - Colyseus Server
+FROM node:18-alpine
+
+# Set working directory
+WORKDIR /app
+
+# Copy package files
+COPY package*.json ./
+
+# Install dependencies
+RUN npm ci --only=production
+
+# Copy source code
+COPY . .
+
+# Build TypeScript
+RUN npm run build
+
+# Expose port
+EXPOSE 2567
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+  CMD curl -f http://localhost:2567/health || exit 1
+
+# Start server
+CMD ["npm", "start"]