Added JWT app prompt

Author: kchandan

Chapter-4/JWT_security.md

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+I have a beginner FastAPI Employee Management app and I want to upgrade it with JWT authentication for teaching purposes.
+
+Please modify the app so students can learn:
+1. login
+2. password verification
+3. JWT creation
+4. token validation
+5. role-based access control
+
+Requirements:
+- FastAPI app
+- one-file implementation preferred
+- hardcoded users only for now
+- admin and user role
+- JWT Bearer token auth
+- protect employee routes
+- beginner-friendly code and explanations
+
+Hardcoded users:
+- admin / admin123 / role=admin
+- user / user123 / role=user
+
+JWT requirements:
+- include username and role in token
+- include expiration
+- validate signature and expiration
+- return 401 for bad token/login
+- return 403 for insufficient role
+
+Route access:
+- GET /employees → admin or user
+- POST /employees → admin only
+- PUT /employees/{id} → admin only
+- DELETE /employees/{id} → admin only
+
+Output required:
+- pip install commands
+- full code
+- run instructions
+- sample login curl
+- sample protected route curl
+- simple explanation of the JWT authentication flow
+
+Keep it simple enough for fresh graduate students to understand and maintain.