fix(go-server): skip readOnly fields in AssertXxxRequired

[halfcrazy]

AssertXxxRequired is only invoked on decoded request bodies, but it enforced every entry of a schema's required list, including readOnly properties. Per OpenAPI 3.x, readOnly properties are produced by the server and MUST NOT be sent by the client, so a schema legitimately listing a readOnly property as required (e.g. Redfish/JSON:API identity fields like id, @odata.type) caused the generated controller to reject every valid request that omitted the readOnly field.

Skip readOnly entries in the requiredVars loop in model.mustache so non-readOnly required fields are still validated while readOnly ones are not enforced on request bodies. Add a regression test using a spec with a readOnly+required id and a non-readOnly required name.
fix #24168

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Summary by cubic

Skip readOnly fields during go-server model validation so request bodies can omit server-produced fields without failing. Non-readOnly required fields are still enforced, and readOnly fields are excluded from required checks, recursion, and constraints, matching OpenAPI 3.

• Bug Fixes
  • Update model.mustache to exclude readOnly fields from the required map, from recursion in AssertXxxRequired, and from AssertXxxConstraints.
  • Add readonly-required.yaml and tests in GoServerCodegenTest to ensure id is skipped, name is enforced, and nested Meta is not recursed into.

^{Written for commit c58951d. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 3 files

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