Add authenticated user profile page with locked-down account endpoint (#315)

web/backend/Features/Features.Users/Dtos/UserDtos.cs

@@ -0,0 +1,10 @@
+namespace Features.Users.Dtos;
+
+/// <summary>Represents the subset of a user account that is safe to expose on a public profile.</summary>
+public record PublicUserProfileDto(
+    Guid UserAccountId,
+    string Username,
+    string FirstName,
+    string LastName,
+    DateTime CreatedAt
+);