feat: add ToErrorOrAsync extension method for Tasks

This improves readability when using ErrorOr for async calls.
E.g.
```
User? user = await userRepository.FindById(id);
ErrorOr<User> userResult = user.ToErrorOr()
    .FailIf(x => x is null, UserErrors.NotFoundById(id))
    .Then(x => x!);
```
becomes
```
ErrorOr<User> user = await userRepository.FindById(id)
    .ToErrorOrAsync()
    .FailIf(x => x is null, UserErrors.NotFoundById(id))
    .Then(x => x!);
```

src/ErrorOr/ErrorOr.ToErrorOrExtensions.cs

@@ -10,6 +10,14 @@ public static ErrorOr<TValue> ToErrorOr<TValue>(this TValue value)
         return value;
     }
 
+    /// <summary>
+    /// Creates an <see cref="ErrorOr{TValue}"/> instance with the result of the given <see cref="Task{TValue}"/>.
+    /// </summary>
+    public static async Task<ErrorOr<TValue>> ToErrorOrAsync<TValue>(this Task<TValue> value)
+    {
+        return await value;
+    }
+
     /// <summary>
     /// Creates an <see cref="ErrorOr{TValue}"/> instance with the given <paramref name="error"/>.
     /// </summary>

tests/ErrorOr/ErrorOr.ToErrorOrTests.cs

@@ -19,6 +19,21 @@ public void ValueToErrorOr_WhenAccessingValue_ShouldReturnValue()
         result.Value.Should().Be(value);
     }
 
+    [Fact]
+    public async Task TaskToErrorOrAsync_WhenAccessingValue_ShouldReturnValue()
+    {
+        // Arrange
+        int value = 5;
+        Task<int> task = Task.FromResult(value);
+
+        // Act
+        ErrorOr<int> result = await task.ToErrorOrAsync();
+
+        // Assert
+        result.IsError.Should().BeFalse();
+        result.Value.Should().Be(value);
+    }
+
     [Fact]
     public void ErrorToErrorOr_WhenAccessingFirstError_ShouldReturnSameError()
     {