#23863 [FEAT][Java] Annotate Generated Enum-classes with `@Generated`

Annotates generated enum-classes with @Generated - both inner and outer. Using ANY java-library. The @Generated-annotation will be imported dynamically based on the choice of Jakarta / JavaX. NOTE: While this is intended to be non-breaking, if this annotation is currently manually added (via configOptions or vendor-extensions), these MUST be removed because @Generated-annotations are NOT repeatable. This fixes #23832

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package || exit
  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
  ./bin/utils/export_docs_generators.sh || exit
  

  (For Windows users, please run the script in WSL)
  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.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.x.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
• If your PR solves a reported issue, reference it using GitHub's linking syntax (e.g., having "fixes #123" present in the PR description)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

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Summary by cubic

Adds @Generated to all generated Java enums (top-level and inner) so tools can recognize and ignore generated code. Aligns enums with other generated classes.

• Bug Fixes

  • Inserted {{>generatedAnnotation}} before enum declarations across Java generators: microprofile, native, okhttp-gson, JavaInflector, JavaJaxRS (CXF, RESTEasy, Spec), JavaSpring, JavaPlayFramework, JavaVertXServer, java-helidon (client mp/se, server mp/se), java-msf4j-server, java-pkmst, java-undertow-server, java-micronaut; excludes java-vertx-web.
  • Emits javax.annotation.Generated or jakarta.annotation.Generated based on generator settings; adds a line break after the annotation.
  • Set hideGenerationTimestamp: true in sample generation configs and regenerated Java samples to include the annotation on all enums.

• Migration

  • No action needed. If you manually add @Generated to enums, remove it to avoid duplicates; and for JDK 9+ with the javax variant, add javax.annotation:javax.annotation-api to the classpath.