[CodeQuality] Add AddIntersectionVarToMockObjectPropertyRector

[TomasVotruba]

Adds new rule AddIntersectionVarToMockObjectPropertyRector.

For a native MockObject property assigned via createMock(X::class) in setUp(), adds a @var \PHPUnit\Framework\MockObject\MockObject&\X docblock so the property carries both the MockObject and the mocked class type.

 private \PHPUnit\Framework\MockObject\MockObject $someServiceMock;
+/**
+ * @var \PHPUnit\Framework\MockObject\MockObject&\SomeService
+ */
+private \PHPUnit\Framework\MockObject\MockObject $someServiceMock;

 protected function setUp(): void
 {
     $this->someServiceMock = $this->createMock(SomeService::class);
 }

Registered in phpunit-code-quality set. Overwrites any existing @var. Covered with tests (basic, overwrite-existing, skip non-MockObject type, skip non-test class).