feat: 添加 Docker 部署支持和多 OCR 提供商架构

- 添加完整的 Docker 配置 (Dockerfile, docker-compose.yml)
- 修复前端硬编码端口 4000，改用相对路径 /api
- 实现多 OCR 提供商架构 (Tesseract.js/Baidu/RapidOCR)
- 修复 Docker 环境中图片上传路径问题
- 添加用户设置页面和 AI 分析服务
- 更新 Prisma schema 支持 AI 分析结果
- 添加部署文档和 OCR 配置指南

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

backend/Dockerfile

@@ -0,0 +1,70 @@
+# ========================================
+# Stage 1: Dependencies
+# ========================================
+FROM node:20-alpine AS deps
+
+RUN apk add --no-cache libc6-compat
+
+WORKDIR /app
+
+# Copy package files
+COPY package*.json ./
+COPY prisma ./prisma/
+
+# Install dependencies
+RUN npm ci
+
+# ========================================
+# Stage 2: Builder
+# ========================================
+FROM node:20-alpine AS builder
+
+WORKDIR /app
+
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+
+# Generate Prisma Client
+RUN npx prisma generate
+
+# Build TypeScript
+RUN npm run build
+
+# ========================================
+# Stage 3: Runner
+# ========================================
+FROM node:20-alpine AS runner
+
+WORKDIR /app
+
+ENV NODE_ENV=production
+
+# Add dumb-init, su-exec and OpenSSL for Prisma
+RUN apk add --no-cache dumb-init su-exec openssl-dev openssl
+
+# Create non-root user
+RUN addgroup -g 1001 -S nodejs && \
+    adduser -S nodejs -u 1001
+
+# Copy necessary files - use tsx to run TypeScript directly
+COPY --from=builder /app/src ./src
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/prisma ./prisma
+COPY --from=builder /app/package*.json ./
+
+# Create uploads directory with proper permissions
+RUN mkdir -p /app/uploads && \
+    chown -R nodejs:nodejs /app
+
+# Copy entrypoint and set permissions
+COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
+RUN chmod +x /usr/local/bin/docker-entrypoint.sh
+
+# Don't switch user here - let entrypoint do it after setting up data dir
+
+EXPOSE 13057
+
+# Use dumb-init to handle signals properly
+# Run as root, entrypoint will switch to nodejs
+ENTRYPOINT ["dumb-init", "--"]
+CMD ["docker-entrypoint.sh"]