Support target: "type_use" for @annotate to avoid deprecated @Valid on containers (fixes #954)

[harshit6392]

Fixes #954

Hibernate Validator 9.x / Jakarta EE 11 deprecates placing cascading-validation
annotations such as @Valid directly on a container type:

@Valid List<Employee> employees; // HV000271 deprecation warning

and recommends annotating the type argument instead:

List<@Valid Employee> employees;

Today the @annotate directive's target option only supports placing the
generated annotation on the field/getter/setter/constructor-parameter
declaration (target: "field" | "get" | "set" | "setparam" | "param"),
so there was no way to reproduce the recommended List<@Valid T> shape.

What this PR does

Adds a new target: "type_use" option for @annotate (Java codegen only).
When used, the annotation is woven into the type itself (JSR‑308 /
type-use style) rather than added as a declaration annotation:

• For a parameterized/container type (e.g. List<Employee>), the annotation
  is applied to the type argument: List<@Valid Employee>.
• For any other type, the annotation is applied to the type itself, e.g.
  @NotNull String.

The resulting type is applied consistently everywhere the field's type is
declared: the field itself, the getter return type, the setter parameter,
and the all-args constructor parameter.

Example

input WorkplaceInput {
    employees: [EmployeeInput!]
        @annotate(name: "jakarta.validation.Valid", target: "type_use")
}

generates:

private List<@Valid EmployeeInput> employees;
...
public List<@Valid EmployeeInput> getEmployees() { ... }
public void setEmployees(List<@Valid EmployeeInput> employees) { ... }

instead of the deprecated @Valid List<EmployeeInput> employees.

Changes

• SiteTarget.kt — new TYPE_USE enum value.
• JavaPoetUtils.kt — new applyTypeUseAnnotations(type, annotations) helper
  that annotates a ParameterizedTypeName's type argument(s), or the type
  itself for non-parameterized types.
• DataTypeGenerator.kt — addField, addGetterAndSetter, and
  addParameterizedConstructor now recognize SiteTarget.TYPE_USE and apply
  the annotation to the type via the new helper instead of as a declaration
  annotation.
• CodeGenTest.kt — two new tests covering the list/container case and the
  plain-type case.

Scope / follow-ups

• This only covers the Java generator, matching the issue's example.
  Kotlin/Kotlin2 codegen (KotlinPoetUtils.kt, Kotlin2*.kt) intentionally
  isn't touched here — happy to add parity there in a follow-up if
  maintainers want it before merging (CONTRIBUTING.md asks for feature
  parity between the two).
• The public docs for the @annotate directive live in the separate
  netflix.github.io/dgs docs site, not in this repo, so they aren't
  updated as part of this PR.

Testing

Added CodeGenTest cases:

• annotateOnTypesWithTargetsOnTypeUse annotates the list type argument instead of the container
• annotateOnTypesWithTargetsOnTypeUse annotates a non-container field type directly

I wasn't able to run ./gradlew test in the environment I prepared this
patch in (no network access to Maven Central / Gradle's distribution
server), so please run the full test suite before merging — happy to fix up
anything that doesn't line up.