style(backend): apply dotnet format whitespace normalization

- Applied dotnet format to 24 files in backend/
- Corrects spacing, indentation, and formatting consistency
- No functional changes to code logic

Ultraworked with Sisyphus <https://github.com/code-yeongyu/oh-my-opencode>
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/WorkClub.Api/Endpoints/Tasks/TaskEndpoints.cs

@@ -47,7 +47,7 @@ public static class TaskEndpoints
         TaskService taskService)
     {
         var result = await taskService.GetTaskByIdAsync(id);
-        
+
         if (result == null)
             return TypedResults.NotFound();
 
@@ -66,7 +66,7 @@ public static class TaskEndpoints
         }
 
         var (task, error) = await taskService.CreateTaskAsync(request, createdById);
-        
+
         if (error != null || task == null)
             return TypedResults.BadRequest(error ?? "Failed to create task");
 
@@ -84,10 +84,10 @@ public static class TaskEndpoints
         {
             if (error == "Task not found")
                 return TypedResults.NotFound();
-            
+
             if (isConflict)
                 return TypedResults.Conflict(error);
-            
+
             return TypedResults.UnprocessableEntity(error);
         }
 
@@ -99,7 +99,7 @@ public static class TaskEndpoints
         TaskService taskService)
     {
         var deleted = await taskService.DeleteTaskAsync(id);
-        
+
         if (!deleted)
             return TypedResults.NotFound();