Add comprehensive tests for iOS DatePicker MinimumDate handling

Co-authored-by: PureWeen <5375137+PureWeen@users.noreply.github.com>

Author: Copilot

src/Core/tests/UnitTests/Views/DatePickerTests.cs

@@ -44,5 +44,20 @@ public void TestDatePickerMinValueHandling()
 			// The DatePicker should have MinimumDate as its value due to coercion
 			Assert.Equal(new DateTime(1900, 1, 1), datePicker.Date);
 		}
+
+		[Fact]
+		public void TestDatePickerWithCustomMinimumDate()
+		{
+			DatePicker datePicker = new DatePicker();
+			
+			// Set a custom minimum date
+			datePicker.MinimumDate = new DateTime(2020, 1, 1);
+			
+			// Set date to MinValue - this should get coerced to the new MinimumDate
+			datePicker.Date = DateTime.MinValue;
+			
+			// The DatePicker should have the custom MinimumDate as its value
+			Assert.Equal(new DateTime(2020, 1, 1), datePicker.Date);
+		}
 	}
 }