Add EntityGraphHint query method parameter

[yeomin4242]

Repository query methods can now accept EntityGraphHint to select an entity graph per invocation.

The hint can be created from type-safe property paths, named entity graphs, or a JPA EntityGraph instance. We treat the hint as a special parameter so it is excluded from query binding and apply it for runtime and AOT query creation. If the argument is null, query creation falls back to the declared @EntityGraph metadata.

Includes unit and integration tests for parameter discovery, runtime query creation, repository execution, and AOT query generation.

Closes #4175

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[jewoodev]

One precedence case seems worth pinning down with a regression test: if a query method declares @EntityGraph and receives a non-null EntityGraphHint, the parameter hint should override the declared graph.

The implementation currently does that, while the tests cover the hint-only path and the null fallback path. Adding a runtime/AOT test for the non-null override case would make the new invocation-level contract explicit.

[yeomin4242]

One precedence case seems worth pinning down with a regression test: if a query method declares @EntityGraph and receives a non-null EntityGraphHint, the parameter hint should override the declared graph.

The implementation currently does that, while the tests cover the hint-only path and the null fallback path. Adding a runtime/AOT test for the non-null override case would make the new invocation-level contract explicit.

@jewoodev Thanks!

I added regression tests for this in both the runtime and AOT paths. The tests invoke a method that declares @EntityGraph with a non-null EntityGraphHint for a different association, then assert that the parameter hint takes effect and the declared graph does not.

That should make the intended precedence explicit: non-null EntityGraphHint overrides the declared graph, while null continues to fall back to @EntityGraph.