[category] (feat/delete-auth): Implemented role based authorization f…

[anamul-hoque-shourov]

📘 Description
Adds role-based JWT authentication to the DELETE /api/v1/categories/{id} endpoint. Only users with the admin role can delete categories. Also updates JWT generation to include role and is_admin claims.

📂 Related Issue
Closes #198

🚀 Changes Made

• Updated handlers.DeleteCategoryByID to enforce admin-only access
• Modified middlewares.AuthenticateJWT to store role and is_admin in the request context
• Added helper function middlewares.IsAdmin(r *http.Request) bool
• Updated util.GenerateToken to include role and is_admin in JWT claims
• Updated tests for token generation and authorization

✅ Checklist

• Follows contribution guidelines
• Tested endpoint with admin and non-admin JWT tokens

[cla-assistant]

All committers have signed the CLA.

[geomachine]

We have further developed the product. please check the product and find another issue and acknowledge. then we will close the pr,