Fixed outer enum issue on jaxrs-resteasy and jaxrs-resteasy-eap

[GabriRuflex]

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Description of the PR

• Fixed outer enum issue on jaxrs-resteasy and jaxrs-reasteasy-eap languages (similar to jaxrs-spec, see [JAXRS-SPEC] Enum values are generating """, "&#3D;", imports are being written inside class declaration #3856)

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@HugoMario

[GabriRuflex]

@HugoMario Hi Hugo, could you please take a look on this? Thanks a lot!

[ellyxc]

Hi there, what is the status of this PR? i think this PR open for about 2 years already

[GabriRuflex]

Hi maintainers 👋

This PR has now been open for almost 6 years (since October 2020), so here's a fresh status update:

The bug is evident, trivially reproducible and blocking. Any Swagger spec that defines a top-level (outer) enum currently produces broken code with these generators — you can reproduce it with a three-line definition:

OrderStatus:
  type: string
  enum: [placed, approved, delivered]

• jaxrs-resteasy: the generated enum does not even compile — the template renders the raw allowableValues map, producing something like public enum OrderStatus { {values=[placed, approved, delivered], enumVars=[...]} }. This is the same class of bug that was fixed for jaxrs-spec in [JAXRS-SPEC] Enum values are generating """, "&#3D;", imports are being written inside class declaration #3856.
• jaxrs-resteasy-eap: the enum compiles but loses the spec values — no value field and no @JsonValue, so Jackson serializes the Java constant name (PLACED) instead of the wire value (placed), breaking round-tripping with any conforming client.

The fix is the missing half of code that is already on master. Interestingly, JavaResteasyServerCodegen and JavaResteasyEapServerCodegen already contain the postProcessModelsEnum logic that adds the com.fasterxml.jackson.annotation.JsonValue import for outer enum models — but the templates were never updated to use it. This PR provides exactly that missing template side.

Current state of the PR:

• ✅ Rebased on the current master, no conflicts, mergeable
• ✅ Now includes regression tests (JavaResteasyOuterEnumTest, parametrized over both generators) that generate from a spec with a top-level enum and verify the emitted code — the tests fail on master and pass with this PR

Given that the change is two mustache templates plus tests, aligns these generators with what jaxrs-spec has done since 2019, and is now covered by regression tests, it would be great to finally get this reviewed and merged. Happy to address any feedback quickly. Thanks! 🙏

cc @ewaostrowska