fix(openapi): emit Draft 4 boolean exclusive bounds for spec 3.0.0

[soyuka]

Summary

OpenAPI 3.0 inherits JSON Schema Draft 4 semantics where exclusiveMinimum / exclusiveMaximum MUST be booleans qualifying minimum / maximum. The runtime SchemaFactory emits the JSON Schema 2020-12 form (these keywords as numbers), so api:openapi:export --spec-version=3.0.0 and GET /docs.jsonopenapi?spec_version=3.0.0 produced invalid 3.0 documents for any property with Assert\Positive, Assert\GreaterThan, Assert\LessThan, or Assert\Range with strict bounds.

BackwardCompatibleSchemaFactory (introduced in #6098 closing #6041) was supposed to handle the conversion but only fires when the serializer context contains draft_4 => true — a flag set today only by ApiTestAssertionsTrait. OpenApiFactory's buildSchema call sites passed serializerContext: null, so the BC conversion never activated in the export / HTTP paths.

Changes

1. OpenApiFactory — derive a schema serializer context from $context['spec_version'] once per collectPaths() call and thread it through every buildSchema() invocation (output, input, error responses). addOperationErrors() gains an optional $serializerContext parameter for the error schemas.

2. BackwardCompatibleSchemaFactory — guard the swap against schemas where exclusiveMinimum / exclusiveMaximum is already boolean. The same property ArrayObject instance is reachable through multiple definitions (one per supported format), and the previous unconditional rewrite turned {minimum: 10, exclusiveMinimum: true} into {minimum: true, exclusiveMinimum: true} on the second pass.

3. OpenApiCommand — thread --spec-version into the OpenApiFactory::__invoke context, not only into the normalizer. Before this, collectPaths() never saw the requested spec version on the CLI path, so the Draft 4 conversion above never activated for api:openapi:export --spec-version=3.0.0. The HTTP path was unaffected because SerializerContextBuilder already injects spec_version into the OpenApiProvider context.

Observed vs expected

Before:

"positive": { "minimum": 0, "exclusiveMinimum": 0, "type": "integer" }

After:

"positive": { "minimum": 0, "exclusiveMinimum": true, "type": "integer" }

Closes #7936
Closes #8176

Test plan

• New functional test OpenApiTest::testOpenApi30EmitsBooleanExclusiveBoundsForNumericConstraints exercises /docs.jsonopenapi?spec_version=3.0.0 against the existing NumericValidated fixture (Assert\GreaterThan, Assert\LessThan, Assert\Positive); fails on the base branch (exclusiveMinimum: 10 number / corruption to minimum: true), green after the fix.
• New OpenApiCommandTest::testSpecVersion30EmitsDraft4BooleanExclusiveBounds exercises api:openapi:export --spec-version=3.0.0 against the same fixture; fails without the OpenApiCommand plumb (exclusiveMinimum: 10), green after the fix.
• BackwardCompatibleSchemaFactoryTest (existing) — still 4/4 green.
• tests/Functional/OpenApiTest — 21/21 green.
• tests/OpenApi/Command/OpenApiCommandTest — 6/6 green.
• ApiTestCaseTest::testAssertMatchesResourceItemAndCollectionJsonSchemaOutputWithRangeAssertions — still green; idempotency guard does not affect the existing draft-4 test trait path.
• OpenApiFactoryTest::testInvoke failure is pre-existing on upstream/4.3 ('Unprocessable entity' vs 'An error occurred' — unrelated 422 description drift).