refactor: 重构后端架构，采用 Go 风格四层设计模式

## 主要变更

### 🏗️ 架构重构
- 采用简洁的四层架构：API → Service → Repository → Model
- 遵循 Go 语言最佳实践和命名规范
- 实现依赖注入和接口导向设计
- 统一错误处理和响应格式

### 📁 目录结构优化
- 删除重复模块 (application/, domain/, infrastructure/ 等)
- 规范化命名 (使用 Go 风格的 snake_case)
- 清理无关文件 (package.json, node_modules/ 等)
- 新增规范化的测试目录结构

### 📚 文档系统
- 为每个模块创建详细的 CLAUDE.md 指导文件
- 包含开发规范、最佳实践和使用示例
- 支持模块化开发，缩短上下文长度

### 🔧 开发规范
- 统一接口命名规范 (UserServicer, PhotoRepositoryr)
- 标准化错误处理机制
- 完善的测试策略 (单元测试、集成测试、性能测试)
- 规范化的配置管理

### 🗂️ 新增文件
- cmd/server/ - 服务启动入口和配置
- internal/model/ - 数据模型层 (entity, dto, request)
- pkg/ - 共享工具包 (logger, response, validator)
- tests/ - 完整测试结构
- docs/ - API 文档和架构设计
- .gitignore - Git 忽略文件配置

### 🗑️ 清理内容
- 删除 Node.js 相关文件 (package.json, node_modules/)
- 移除重复的架构目录
- 清理临时文件和构建产物
- 删除重复的文档文件

## 影响
- 提高代码可维护性和可扩展性
- 统一开发规范，提升团队协作效率
- 优化项目结构，符合 Go 语言生态标准
- 完善文档体系，降低上手难度

backend/configs/config.dev.yaml

@@ -0,0 +1,105 @@
+# 开发环境配置
+app:
+  name: "Photography Portfolio Dev"
+  version: "1.0.0"
+  environment: "development"
+  port: 8080
+  debug: true
+
+# 数据库配置
+database:
+  host: "localhost"
+  port: 5432
+  username: "postgres"
+  password: "password"
+  database: "photography_dev"
+  ssl_mode: "disable"
+  max_open_conns: 50
+  max_idle_conns: 5
+  conn_max_lifetime: 300
+
+# Redis配置
+redis:
+  host: "localhost"
+  port: 6379
+  password: ""
+  database: 1
+  pool_size: 10
+  min_idle_conns: 2
+
+# JWT配置
+jwt:
+  secret: "dev-secret-key-not-for-production"
+  expires_in: "24h"
+  refresh_expires_in: "168h"
+
+# 存储配置
+storage:
+  type: "local"
+  local:
+    base_path: "./uploads"
+    base_url: "http://localhost:8080/uploads"
+  s3:
+    region: "us-east-1"
+    bucket: "photography-dev-bucket"
+    access_key: ""
+    secret_key: ""
+    endpoint: ""
+
+# 上传配置
+upload:
+  max_file_size: 104857600  # 100MB
+  allowed_types:
+    - "image/jpeg"
+    - "image/jpg"
+    - "image/png"
+    - "image/gif"
+    - "image/webp"
+    - "image/tiff"
+    - "image/bmp"
+  thumbnail_sizes:
+    - name: "thumbnail"
+      width: 200
+      height: 200
+    - name: "medium"
+      width: 800
+      height: 600
+    - name: "large"
+      width: 1920
+      height: 1080
+
+# 日志配置
+logger:
+  level: "debug"
+  format: "text"
+  output: "stdout"
+  filename: "logs/dev.log"
+  max_size: 50
+  max_age: 7
+  compress: false
+
+# CORS配置
+cors:
+  allowed_origins:
+    - "http://localhost:3000"
+    - "http://localhost:3001"
+    - "http://localhost:5173"
+  allowed_methods:
+    - "GET"
+    - "POST"
+    - "PUT"
+    - "DELETE"
+    - "PATCH"
+    - "OPTIONS"
+  allowed_headers:
+    - "Content-Type"
+    - "Authorization"
+    - "X-Requested-With"
+    - "Origin"
+  allow_credentials: true
+
+# 限流配置
+rate_limit:
+  enabled: false
+  requests_per_minute: 1000
+  burst: 2000

backend/configs/config.prod.yaml

@@ -0,0 +1,101 @@
+# 生产环境配置
+app:
+  name: "Photography Portfolio"
+  version: "1.0.0"
+  environment: "production"
+  port: 8080
+  debug: false
+
+# 数据库配置
+database:
+  host: "localhost"
+  port: 5432
+  username: "postgres"
+  password: "${DB_PASSWORD}"
+  database: "photography"
+  ssl_mode: "require"
+  max_open_conns: 200
+  max_idle_conns: 20
+  conn_max_lifetime: 3600
+
+# Redis配置
+redis:
+  host: "localhost"
+  port: 6379
+  password: "${REDIS_PASSWORD}"
+  database: 0
+  pool_size: 50
+  min_idle_conns: 10
+
+# JWT配置
+jwt:
+  secret: "${JWT_SECRET}"
+  expires_in: "24h"
+  refresh_expires_in: "168h"
+
+# 存储配置
+storage:
+  type: "local"  # 生产环境建议使用 s3 或 oss
+  local:
+    base_path: "/var/www/photography/uploads"
+    base_url: "https://photography.iriver.top/uploads"
+  s3:
+    region: "${AWS_REGION}"
+    bucket: "${AWS_BUCKET}"
+    access_key: "${AWS_ACCESS_KEY_ID}"
+    secret_key: "${AWS_SECRET_ACCESS_KEY}"
+    endpoint: "${AWS_ENDPOINT}"
+
+# 上传配置
+upload:
+  max_file_size: 104857600  # 100MB
+  allowed_types:
+    - "image/jpeg"
+    - "image/jpg"
+    - "image/png"
+    - "image/gif"
+    - "image/webp"
+    - "image/tiff"
+  thumbnail_sizes:
+    - name: "thumbnail"
+      width: 200
+      height: 200
+    - name: "medium"
+      width: 800
+      height: 600
+    - name: "large"
+      width: 1920
+      height: 1080
+
+# 日志配置
+logger:
+  level: "info"
+  format: "json"
+  output: "file"
+  filename: "/var/log/photography/app.log"
+  max_size: 100
+  max_age: 30
+  compress: true
+
+# CORS配置
+cors:
+  allowed_origins:
+    - "https://photography.iriver.top"
+    - "https://admin.photography.iriver.top"
+  allowed_methods:
+    - "GET"
+    - "POST"
+    - "PUT"
+    - "DELETE"
+    - "OPTIONS"
+  allowed_headers:
+    - "Content-Type"
+    - "Authorization"
+    - "X-Requested-With"
+  allow_credentials: true
+
+# 限流配置
+rate_limit:
+  enabled: true
+  requests_per_minute: 60
+  burst: 120