Allow request bodies on DELETE in the Kotlin client (multiplatform and jvm-ktor)

[walterbrebels]

Add RequestMethod.DELETE to the bodied-methods list in the Kotlin client
multiplatform and jvm-ktor ApiClient.kt.mustache templates.

Motivation

RFC 9110 §9.3.5 permits a payload on DELETE. Several real-world APIs
require a body on DELETE (e.g. bulk-delete payloads, soft-delete options).
With the current templates, the generated client silently drops the body
on DELETE, so spec-defined requestBody on a DELETE operation cannot be
sent. The fix mirrors the existing PUT/POST/PATCH handling.

Scope

• kotlin-client/libraries/multiplatform/infrastructure/ApiClient.kt.mustache
• kotlin-client/libraries/jvm-ktor/infrastructure/ApiClient.kt.mustache

Samples regenerated for all affected configs.

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work.
• Built with ./mvnw clean package and ran ./bin/generate-samples.sh
  for all kotlin-multiplatform/jvm-ktor configs;
  ./bin/utils/export_docs_generators.sh produced no diff.
  Note: bin/configs/unmaintained/kotlin-multiplatform.yaml fails
  independently (pre-existing dateLibrary config bug), so the
  corresponding sample under samples/openapi3/.../kotlin-multiplatform
  was not regenerated.
• Targeted at master.
• No linked issue.
• Kotlin technical committee: @wing328 @jimschubert @cbornet @bjoernblomqvist @4brunu @yutaka0m

---

Summary by cubic

Allow request bodies on DELETE in the Kotlin client multiplatform and jvm-ktor templates so generated clients no longer drop requestBody for DELETE operations, aligning with RFC 9110.

• Bug Fixes
  • Treat DELETE as a bodied method in ApiClient.kt.mustache for multiplatform and jvm-ktor (mirrors PUT/POST/PATCH handling).
  • Regenerated affected Kotlin samples to reflect the change.

^{Written for commit 138dd1a. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 13 files

[walterbrebels]

/rerun-failed

[wing328]

thanks for the fix, which has been merged