refactor(enum-utils): move normalization logic for enum handling to EnumUtils

[Mattias-Sehlstedt]

This moves the remaining logic for enum processing in the OpenAPINormalizer to the EnumUtils.

This is done to centralize the logic for Enum processing, with the goal of being able to introduce a more explicit CodegenEnum model to carry the reoccurring Enum logic.

After this PR the OpenAPI representation -> Normalized OpenAPI representation step of the overall generator process

Specification -> 
OpenAPI representation -> 
Normalized OpenAPI representation -> 
Codegen models -> 
Code generated with mustache-templates

has been handled.

This should mean that we can now investigate Normalized OpenAPI representation -> Codegen model, which is the step that would contain CodegenEnum.

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Note that this intentionally removes the protected method Schema createSimplifiedEnumSchema(...) from the OpenAPINormalizer.

This is done since I do not believe it is a logical extension point for a user, and that it rather only is a helper for the main rule method (Schema simplifyComposedSchemaWithEnums(...)). Thus that it belongs entirely in the Utils class. This is also based around the reasoning that the Normalizer mainly has one protected method per rules, so that if the user wants to adjust a rule, then they mainly override the entire rule-method.

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Summary by cubic

Centralizes enum normalization in EnumUtils, moving logic out of OpenAPINormalizer. Unifies oneOf/anyOf (including OAS 3.1 const) into a single enum while preserving type and enum metadata.

• Refactors

  • Added EnumUtils.simplifyComposedSchemaWithEnums(schema, subSchemas, composedType, openAPI) to resolve $refs and merge enum/const sub-schemas, preserving type, x-enum-descriptions, and x-enum-deprecated.
  • OpenAPINormalizer.simplifyComposedSchemaWithEnums(...) now delegates to EnumUtils and logs a standardized debug message when simplification occurs.
  • Consolidated enum-building helpers inside EnumUtils (now private), and introduced EnumUtils.ONE_OF/EnumUtils.ANY_OF constants for consistency.

• Migration

  • Removed protected OpenAPINormalizer.createSimplifiedEnumSchema(...). If you customized it, override simplifyComposedSchemaWithEnums(...) instead.

^{Written for commit 0861724. Summary will update on new commits.}

[cubic-dev-ai]

All reported issues were addressed across 2 files

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