#25355 [php] Keep the model namespace for allOf-wrapped array items and parameters

fix #25354

AbstractPhpCodegen.toAllOfName() returns the fully qualified type declaration of each allOf member. For an inline allOf with a single $ref (an array item or a parameter schema; properties are unwrapped earlier by DefaultCodegen.fromProperty()), that qualified name is what getSchemaType() receives, and toModelName() then strips the namespace separators, so php and php-nextgen emit types like \AcmeClientModelError[] and ?\AcmeClientModelSortDir that reference classes that do not exist.

This change mirrors the existing property handling:

• toAllOfName(): with a single member, defer to the default implementation so a bare schema name comes back and baseType/complexType match the plain $ref case.
• getTypeDeclaration(Schema): resolve a single-member allOf to its member's declaration, which the existing $ref branch qualifies with the model package.

Multi-member allOf (the A&B intersection form) is unchanged.

Tests

• New PhpModelTest::complexListPropertyWithAllOfItems, which fails on master with expected [\OpenAPI\Client\Model\Children[]] but found [\OpenAPIClientModelChildren[]].
• PhpModelTest, AbstractPhpCodegenTest, PhpClientCodegenTest, PhpNextgenClientCodegenTest: 57 tests, 0 failures.
• The minimal spec from the issue now generates '\Acme\Client\Model\Error[]' and ?\Acme\Client\Model\SortDir for both generators.
• A large real-world spec (14.8k lines, 316 models, 306 affected references) generated with this change is byte-identical to 7.26.0 output with the separators restored by post-processing, so there are no side effects beyond the mangled names.

Second commit: the issue's spec is now a fixture (src/test/resources/bugs/issue_25354.yaml) with a generation-level test in both PhpClientCodegenTest and PhpNextgenClientCodegenTest asserting the model type map and the API parameter, and the php-nextgen petstore sample spec gains an AllOfRefArray model so the regenerated samples/client/petstore/php-nextgen shows the fix ('tags' => '\OpenAPI\Client\Model\Tag[]') and the php-nextgen phpstan job exercises it. All 15 bin/configs/php* samples regenerated; only that sample changed.
PHP technical committee: @jebentier @dkarlovi @mandrean @jfastnacht @ybelenko @renepardon

PR checklist

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  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
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  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
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🤖 Generated with Claude Code

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Summary by cubic

Fixes #25354 (PHP): single-member allOf schemas that wrap a $ref — such as array items and parameters — now generate correctly namespaced model names. Previously they produced mangled types like \AcmeClientModelError[] because toAllOfName() returned a fully qualified name that getSchemaType() stripped of namespace separators. Multi-member allOf (the A&B intersection form) is unchanged.

Bug Fixes

• toAllOfName() returns the member's plain schema name for single members, so x-all-of-name is ignored consistently with getTypeDeclaration().
• getTypeDeclaration(Schema) resolves a single-member allOf to the member's declaration so the $ref branch applies the model package.
• Adds complexListPropertyWithAllOfItems to PhpModelTest, generation-level tests in PhpClientCodegenTest/PhpNextgenClientCodegenTest using a new issue_25354.yaml fixture, and an AllOfRefArray model in the php-nextgen petstore sample.
• Leaves the sample's AllOfRefArrayTest.php out of the generated FILES manifest since test files are generated once and skipped when they exist.