Add JWT authentication.

Add: JWT authentication in Web API. Related configuration and services are added.

OptixServe.Core/Services/UserService.cs

@@ -7,6 +7,7 @@ public interface IUserService
 {
     IEnumerable<User> GetUsers();
     User? GetUserById(string id);
+    User? GetUserByUsername(string username);
 }
 
 public class UserService(AppDbContext dbContext) : IUserService
@@ -18,6 +19,11 @@ public class UserService(AppDbContext dbContext) : IUserService
         return _dbContext.Users.FirstOrDefault(u => u.Id == id);
     }
 
+    public User? GetUserByUsername(string username)
+    {
+        return _dbContext.Users.FirstOrDefault(u => u.UserName == username);
+    }
+
     public IEnumerable<User> GetUsers()
     {
         return _dbContext.Users.AsEnumerable();