chore: bump inter-package constraints to ^5.0@alpha

Completes 22ece5199 (open 5.0 dev line): root is 5.0.x-dev but the
self-referential api-platform/* constraints were left at ^4.4@alpha,
which is unresolvable in the component split-tests (published 4.4
alphas require metadata ^4.4, conflicting with the 5.0 root).

chore: require ^4.4@alpha for inter-package dependencies

#7115 added cross-package calls new in 4.4 — getStateOptionsRepositoryMethod()
in api-platform/state and the repositoryMethod constructor argument in
api-platform/doctrine-common — that 4.4 provider code invokes. The old
^4.2/^4.3 sibling floors let `composer update --prefer-lowest` pull releases
lacking these symbols, so the per-component lowest CI jobs failed with
"undefined method" / "unknown named parameter".

Floor all api-platform/* inter-package constraints at ^4.4. The @Alpha
stability flag is required because the subpackages set minimum-stability:beta,
under which a plain ^4.4 would not match the 4.4.0-alpha prereleases. Revert
to plain ^4.4 once 4.4.0 stable ships.

Merge 4.3

refactor(jsonapi): single source of truth for the attribute/relations…

…hip split (#8325)

refactor(jsonapi): single source of truth for the attribute/relations…

…hip split (#8325)

Merge 4.2 into 4.3

Merge 4.2 into 4.3

Merge 4.1 into 4.2

fix(serializer): validate IRI target class on relation denormalization

AbstractItemNormalizer's relation IRI denormalization loaded the
resource without checking it matched the declared relation class,
since it never passed an operation to IriConverter::getResourceFromIri.
A writable relation declared as `Foo` with no PHP type hint (legacy
`@var`-only style) silently accepted a `/bars/1` IRI and Symfony's
PropertyAccessor could not block it — CWE-843 type confusion.

Add an is_a guard at both inline call sites so a mismatched IRI throws
InvalidArgumentException, mirroring the IriConverter operation check.

GHSA-9rjg-x2p2-h68h

fix(jsonapi): allow opt-in client-generated IDs on POST per spec (#7930)

Co-authored-by: soyuka <soyuka@users.noreply.github.com>