Add HTTP QUERY method support (RFC 10008)

[ewalsh]

Pull Request Checklist

• Have you read through the contributor guidelines?
• Have you squashed your commits?
• Have you added copyright headers to new files?
• Have you checked that both Scala and Java APIs are updated?
• Have you updated the documentation for both Scala and Java sections?
• Have you added tests for any changed functionality?

Purpose

Adds first-class support for the HTTP QUERY method (RFC 10008) to play-ws-standalone.

QUERY is a safe, idempotent method that carries a request body — semantically like GET but with POST-style body support. This is useful for complex search queries that don't fit in a URL query string.

Background Context

The implementation mirrors the existing post/put/patch pattern exactly:

• Scala trait: def query[T: BodyWritable](body: T): Future[Response]
• Java interface: CompletionStage<? extends StandaloneWSResponse> query(BodyWritable body)
• AHC implementations: delegate to withBody(body).execute("QUERY") / setMethod("QUERY").setBody(body).execute()

AHC does not strip the body for custom/unknown method strings — verified via unit tests and integration tests against a mock server.

Changes

File	Change
play-ws-standalone/.../StandaloneWSRequest.scala	Added query to Scala trait
play-ws-standalone/.../StandaloneWSRequest.java	Added query to Java interface
play-ahc-ws-standalone/.../StandaloneAhcWSRequest.scala	Scala AHC implementation
play-ahc-ws-standalone/.../StandaloneAhcWSRequest.java	Java AHC implementation
build.sbt	MiMa exclusions for new abstract method
README.md	Usage examples for Scala and Java
Unit tests (Scala + Java)	5 tests verifying method, body, content-type
Integration test	End-to-end test against mock server
.gitignore	Housekeeping: added .metals/ and .vscode/

Validation

• sbt validateCode — ✅ (headerCheckAll, scalafmtSbtCheck, scalafmtCheckAll)
• sbt mimaReportBinaryIssues — ✅ (with exclusions for the new abstract method)
• sbt +test — ✅ (153 tests pass on both Scala 2.13.18 and 3.3.8)

References

• RFC 10008 — HTTP QUERY Method

[ewalsh]

Thanks for the review @cchantep! All feedback addressed in the latest push:

#	Comment	Resolution
1	Empty scaladoc on query impl	Added one-liner: /** Performs a QUERY request. */
2–5	Use must_=== / and blocks in Scala tests	Applied throughout
6	Use must_=== / and blocks in Java tests	Applied
7	.gitignore — IDE specific	Reverted entirely

Apologies for the force-push — should have been a fixup commit to preserve review context. Happy to squash on merge if that's the preferred workflow here.