feat(auth): Implement complete logout functionality with Redis token blacklist and HTTP-only cookie authentication

[zaibamachhaliya]

📋 Summary

This PR adds complete logout functionality with backend token invalidation using Redis blacklist and HTTP-only cookies for secure authentication.

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🚀 What's New?

Backend Changes (8 files)

File	Change
server/config/redis.js	NEW - Redis connection configuration
server/controllers/userController.js	Added logoutUser function with token blacklist
server/middleware/authenticationUser.js	Added Redis blacklist check in auth middleware
server/routes/routers.js	Added POST /logout route
server/index.js	Added cookie-parser & updated CORS credentials
server/package.json	Added redis and cookie-parser dependencies

Frontend Changes (7 files)

File	Change
client/src/components/ProtectedRoute.tsx	NEW - Route protection component
client/src/components/Home/Home.tsx	Added handleLogout function with API call
client/src/components/Authentication/Login.tsx	Migrated to cookie-based auth (removed localStorage)
client/src/components/Authentication/Register.tsx	Migrated to cookie-based auth (removed localStorage)
client/src/services/api.ts	Added withCredentials: true
client/src/App.tsx	Wrapped /home route with ProtectedRoute
client/src/main.tsx	Fixed duplicate Router issue

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🔒 Security Improvements

Issue	Fix
XSS attack on token	✅ HTTP-only cookies (inaccessible to JavaScript)
Token reuse after logout	✅ Redis blacklist with TTL
URL bypass after logout	✅ ProtectedRoute component redirects to login
CSRF attacks	✅ SameSite=Lax cookie attribute

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🧪 Testing Done

• Login sets HTTP-only cookie in browser
• Cookie sent with subsequent API requests
• Logout clears cookie from browser
• Logout adds token to Redis blacklist
• Blacklisted token returns 401 on /auth call
• Manual URL /home redirects to login after logout
• Page refresh maintains session until logout

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📊 Files Changed Summary

Type	New Files	Modified Files	Total
Backend	1 (redis.js)	7	8
Frontend	1 (ProtectedRoute.tsx)	6	7
Total	2	13	15

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🔧 Technologies Used

• Redis - Token blacklist storage with TTL
• cookie-parser - HTTP-only cookie handling
• JWT - Token generation and verification
• Axios - withCredentials for cross-origin cookies
• React Router - ProtectedRoute for route protection

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✅ Related Issue

Closes #6 (Logout Functionality)

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🔨 Latest commit	6491252