fix(graphql): dispatch item Query through its own provider

[soyuka]

Summary

Fixes #5805 — GraphQl item Query(provider: X) was silently ignored: GraphQl\State\Provider\ReadProvider routed item lookups through IriConverter::getResourceFromIri, which dispatched to the route-matched HTTP item op (NotExposed/Get) — bypassing the user-declared Query provider.

The first iteration of this PR copied Query.provider onto the synthesised NotExposed (band-aid scoped to the no-HTTP-Get case). After exploring three alternatives, this PR moves the fix to the dispatch layer so it covers all combinations of HTTP/GraphQl operations.

Implementation (Path A — metadata-time)

1. ReadProvider passes the GraphQl Query to IriConverter when it carries a provider

src/GraphQl/State/Provider/ReadProvider.php — for item Query with provider:, pass the operation as the 3rd argument to iriConverter->getResourceFromIri. Mutation/Subscription keep the route-matched HTTP op so the class-mismatch diagnostic (Item ... did not match expected type ...) stays accurate.

2. IriConverter dispatches via the caller's GraphQl op when it has a provider

src/Symfony/Routing/IriConverter.php + src/Laravel/Routing/IriConverter.php — uri_variables still extracted via the HTTP routeOperation. The final dispatch chooses $operation (GraphQl with provider) over $routeOperation (HTTP).

3. GraphQl Query.links gets the identifier-self link

src/Metadata/Resource/Factory/LinkResourceMetadataCollectionFactory.php — non-collection GraphQl ops get LinkFactory::createLinksFromIdentifiers($op) merged into links. Mirrors what UriTemplateResourceMetadataCollectionFactory already does for HTTP uri_variables.

4. Doctrine LinksHandler filters root-mode walks

src/Doctrine/Common/State/LinksHandlerTrait::getLinks — when no $context['linkClass'] and the op is a GraphQlOperation, keep only links with toClass === null || toClass === $resourceClass. Drops relation links (which target other classes) so handleLinks applies WHERE id = X cleanly. HTTP path unchanged — uri_variables carry no relation-to-other-class links. Doctrine ODM picks the fix up via the shared trait.

src/Laravel/Eloquent/State/LinksHandler — standalone impl, mirror branch added for GraphQl root items.

5. Reverted

NotExposedOperationResourceMetadataCollectionFactory — band-aid no longer needed.

Why this approach

Considered:

• Original PR: metadata-time NotExposed.provider inheritance. Works for operations: [] only. Misses #[Get, Query(provider: X)].
• Path B: runtime injection at dispatch site (clone Query op with HTTP uri_variables copied into links). Local, lower BC blast radius — but implicit transient mutation.
• Path A (this PR): GraphQl Query.links permanently carries the identifier-self link. Symmetric with HTTP uri_variables. Consumer-side filter (4) keeps existing nested-traversal and HTTP behaviour intact.

Path A picked for architectural symmetry — Query.links becomes the single source of truth, mirroring HTTP uri_variables. The LinksHandler filter is a localised change with HTTP unaffected (verified via Subresource tests).

BC

Targets 4.3. Three risk vectors audited:

• IdentifiersExtractor::getIdentifiersFromOperation GraphQl branch reads $op->getLinks() — gets an extra identifier entry. Tests pass.
• ReadLinkParameterProvider::getUriVariables same — tests pass.
• Custom Doctrine LinksHandlerInterface impls walking Query.getLinks() directly would see one extra entry. Documented as a fix.

Test plan

• tests/Functional/GraphQl/GraphQlCustomQueryProviderTest.php — 3 cases: no-HTTP-Get + Query(provider:X), #[Get(provider:Y), Query(provider:X)] (Query wins on GraphQl), HTTP Get keeps own provider.
• Fixtures use static-method providers — no DI, no service registration.
• vendor/bin/phpunit tests/Functional/GraphQl — 150 pass, 0 failures.
• vendor/bin/phpunit tests/Symfony/Routing src/Laravel/Tests/Unit/Routing — 31 pass (IriConverter).
• vendor/bin/phpunit tests/Functional/SubResource tests/Functional/CustomIdentifierWithSubresourceTest.php — 26 pass (HTTP sub-resource unchanged).
• vendor/bin/phpunit src/GraphQl/Tests src/Metadata/Tests — only preexisting baseline failures unrelated to this PR.
• Renamed tests/Fixtures/.../Issue5805/ → GraphQlCustomQueryProvider/ per CLAUDE.md naming rule.