feat: add Docker deployment support

- Add Dockerfile with Node.js 18 alpine build
- Add docker-compose.yml with environment configuration
- Add docs/DOCKER.md deployment guide
- Update README.md with Docker quick start section
- Server binds to 0.0.0.0:3333 for external access
- UI available at http://localhost:3333/ui/
- Volumes mounted for reports and evidence persistence

Dockerfile

@@ -0,0 +1,36 @@
+# syntax=docker/dockerfile:1
+
+FROM node:18-alpine
+
+# Install dependencies
+RUN apk add --no-cache \
+    bash \
+    curl \
+    git \
+    openssl \
+    ca-certificates
+
+WORKDIR /app
+
+# Copy package files
+COPY package*.json ./
+COPY tsconfig.json ./
+
+# Install dependencies
+RUN npm ci && \
+    npm cache clean --force
+
+# Copy source code
+COPY . .
+
+# Build TypeScript
+RUN npm run build
+
+# Ensure docs directory exists for /ui static files
+RUN mkdir -p docs
+
+# Expose port
+EXPOSE 3333
+
+# Default command: run the server (not interactive CLI)
+CMD ["npm", "run", "server"]