feat: Complete implementation of Tasks 1-5 - CIM Document Processor

Backend Infrastructure:
- Complete Express server setup with security middleware (helmet, CORS, rate limiting)
- Comprehensive error handling and logging with Winston
- Authentication system with JWT tokens and session management
- Database models and migrations for Users, Documents, Feedback, and Processing Jobs
- API routes structure for authentication and document management
- Integration tests for all server components (86 tests passing)

Frontend Infrastructure:
- React application with TypeScript and Vite
- Authentication UI with login form, protected routes, and logout functionality
- Authentication context with proper async state management
- Component tests with proper async handling (25 tests passing)
- Tailwind CSS styling and responsive design

Key Features:
- User registration, login, and authentication
- Protected routes with role-based access control
- Comprehensive error handling and user feedback
- Database schema with proper relationships
- Security middleware and validation
- Production-ready build configuration

Test Coverage: 111/111 tests passing
Tasks Completed: 1-5 (Project setup, Database, Auth system, Frontend UI, Backend infrastructure)

Ready for Task 6: File upload backend infrastructure

backend/src/config/env.ts

@@ -0,0 +1,160 @@
+import dotenv from 'dotenv';
+import Joi from 'joi';
+
+// Load environment variables
+dotenv.config();
+
+// Environment validation schema
+const envSchema = Joi.object({
+  NODE_ENV: Joi.string().valid('development', 'production', 'test').default('development'),
+  PORT: Joi.number().default(5000),
+  
+  // Database
+  DATABASE_URL: Joi.string().required(),
+  DB_HOST: Joi.string().default('localhost'),
+  DB_PORT: Joi.number().default(5432),
+  DB_NAME: Joi.string().required(),
+  DB_USER: Joi.string().required(),
+  DB_PASSWORD: Joi.string().required(),
+  
+  // Redis
+  REDIS_URL: Joi.string().default('redis://localhost:6379'),
+  REDIS_HOST: Joi.string().default('localhost'),
+  REDIS_PORT: Joi.number().default(6379),
+  
+  // JWT
+  JWT_SECRET: Joi.string().required(),
+  JWT_EXPIRES_IN: Joi.string().default('1h'),
+  JWT_REFRESH_SECRET: Joi.string().required(),
+  JWT_REFRESH_EXPIRES_IN: Joi.string().default('7d'),
+  
+  // File Upload
+  MAX_FILE_SIZE: Joi.number().default(104857600), // 100MB
+  UPLOAD_DIR: Joi.string().default('uploads'),
+  ALLOWED_FILE_TYPES: Joi.string().default('application/pdf'),
+  
+  // LLM
+  LLM_PROVIDER: Joi.string().valid('openai', 'anthropic').default('openai'),
+  OPENAI_API_KEY: Joi.string().when('LLM_PROVIDER', {
+    is: 'openai',
+    then: Joi.required(),
+    otherwise: Joi.optional()
+  }),
+  ANTHROPIC_API_KEY: Joi.string().when('LLM_PROVIDER', {
+    is: 'anthropic',
+    then: Joi.required(),
+    otherwise: Joi.optional()
+  }),
+  LLM_MODEL: Joi.string().default('gpt-4'),
+  LLM_MAX_TOKENS: Joi.number().default(4000),
+  LLM_TEMPERATURE: Joi.number().min(0).max(2).default(0.1),
+  
+  // Storage
+  STORAGE_TYPE: Joi.string().valid('local', 's3').default('local'),
+  AWS_ACCESS_KEY_ID: Joi.string().when('STORAGE_TYPE', {
+    is: 's3',
+    then: Joi.required(),
+    otherwise: Joi.optional()
+  }),
+  AWS_SECRET_ACCESS_KEY: Joi.string().when('STORAGE_TYPE', {
+    is: 's3',
+    then: Joi.required(),
+    otherwise: Joi.optional()
+  }),
+  AWS_REGION: Joi.string().when('STORAGE_TYPE', {
+    is: 's3',
+    then: Joi.required(),
+    otherwise: Joi.optional()
+  }),
+  AWS_S3_BUCKET: Joi.string().when('STORAGE_TYPE', {
+    is: 's3',
+    then: Joi.required(),
+    otherwise: Joi.optional()
+  }),
+  
+  // Security
+  BCRYPT_ROUNDS: Joi.number().default(12),
+  RATE_LIMIT_WINDOW_MS: Joi.number().default(900000), // 15 minutes
+  RATE_LIMIT_MAX_REQUESTS: Joi.number().default(100),
+  
+  // Logging
+  LOG_LEVEL: Joi.string().valid('error', 'warn', 'info', 'debug').default('info'),
+  LOG_FILE: Joi.string().default('logs/app.log'),
+}).unknown();
+
+// Validate environment variables
+const { error, value: envVars } = envSchema.validate(process.env);
+
+if (error) {
+  throw new Error(`Config validation error: ${error.message}`);
+}
+
+// Export validated configuration
+export const config = {
+  env: envVars.NODE_ENV,
+  nodeEnv: envVars.NODE_ENV,
+  port: envVars.PORT,
+  frontendUrl: process.env['FRONTEND_URL'] || 'http://localhost:3000',
+  
+  database: {
+    url: envVars.DATABASE_URL,
+    host: envVars.DB_HOST,
+    port: envVars.DB_PORT,
+    name: envVars.DB_NAME,
+    user: envVars.DB_USER,
+    password: envVars.DB_PASSWORD,
+  },
+  
+  redis: {
+    url: envVars.REDIS_URL,
+    host: envVars.REDIS_HOST,
+    port: envVars.REDIS_PORT,
+  },
+  
+  jwt: {
+    secret: envVars.JWT_SECRET,
+    expiresIn: envVars.JWT_EXPIRES_IN,
+    refreshSecret: envVars.JWT_REFRESH_SECRET,
+    refreshExpiresIn: envVars.JWT_REFRESH_EXPIRES_IN,
+  },
+  
+  upload: {
+    maxFileSize: envVars.MAX_FILE_SIZE,
+    uploadDir: envVars.UPLOAD_DIR,
+    allowedFileTypes: envVars.ALLOWED_FILE_TYPES.split(','),
+  },
+  
+  llm: {
+    provider: envVars.LLM_PROVIDER,
+    openaiApiKey: envVars.OPENAI_API_KEY,
+    anthropicApiKey: envVars.ANTHROPIC_API_KEY,
+    model: envVars.LLM_MODEL,
+    maxTokens: envVars.LLM_MAX_TOKENS,
+    temperature: envVars.LLM_TEMPERATURE,
+  },
+  
+  storage: {
+    type: envVars.STORAGE_TYPE,
+    aws: {
+      accessKeyId: envVars.AWS_ACCESS_KEY_ID,
+      secretAccessKey: envVars.AWS_SECRET_ACCESS_KEY,
+      region: envVars.AWS_REGION,
+      bucket: envVars.AWS_S3_BUCKET,
+    },
+  },
+  
+  security: {
+    bcryptRounds: envVars.BCRYPT_ROUNDS,
+    rateLimit: {
+      windowMs: envVars.RATE_LIMIT_WINDOW_MS,
+      maxRequests: envVars.RATE_LIMIT_MAX_REQUESTS,
+    },
+  },
+  
+  logging: {
+    level: envVars.LOG_LEVEL,
+    file: envVars.LOG_FILE,
+  },
+};
+
+export default config;