✨ Add query and queryUri for the HTTP QUERY method (RFC 10008)

[CaiJingLong]

Summary

• Add Dio.query and Dio.queryUri convenience methods for the HTTP QUERY method defined in RFC 10008.
• The QUERY method is safe and idempotent like GET, but allows a request body, which is useful for complex queries whose parameters are too large or too structured to fit in the request URI.
• This is a purely additive change: the new methods follow the same pattern as the existing get/post/put/patch/delete/head convenience methods and delegate to request/requestUri with checkOptions('QUERY', options). No existing public API is changed, and all adapters already pass the method string through (HttpClient.openUrl on native, XMLHttpRequest.open on Web), so no adapter changes are required.
• Updated CHANGELOG.md, README.md, and README-ZH.md.

Closes #2548

Verification

• melos run format — pass
• melos run analyze — pass
• dart test test/test_suite_test.dart (dio, VM) — the two new QUERY tests pass, along with the rest of the HTTP method group. A few pre-existing failures in basic_tests and timeout_tests are environment-specific (DNS resolution / TLS handshake / download throughput on the local machine) and unrelated to this change.

AI attribution

Implementation, tests, and docs by Devin (GLM-5.2).

Generated with Devin

[AlexV525]

The PR title and description cite RFC 9239, but that RFC is actually Updates to ECMAScript Media Types (defining text/javascript etc.) — unrelated to the HTTP QUERY method.

The correct reference is RFC 10008, published 2026-06-15 on the IETF Standards Track (Proposed Standard). The code, CHANGELOG, and README in this PR already cite 10008 correctly — only the PR title and description need to be updated to match.

FYI: Proposed Standard is the first formal stage of the IETF standards process (the same status HTTP/2 RFC 7540 and HTTP/3 RFC 9114 had at initial publication), not an Internet-Draft — so the adaptation itself is legitimate.

[CaiJingLong]

Thanks for the catch, @AlexV525. The PR title and description have been updated to reference RFC 10008 instead of RFC 9239. The code, CHANGELOG.md, README.md, and README-ZH.md already cited RFC 10008 correctly (fixed in c3e7a18), so no further code changes were needed.

[AlexV525]

The method doesn't need this full comment because we also enable the request payload for GET in dio. Align with others. The same goes for queryUri.

[CaiJingLong]

Done. The doc comments on query and queryUri are trimmed to a single line each, matching the style of get/post/put/patch/delete/head. See ee8a0fa.

[github-actions]

Code Coverage Report: Only Changed Files listed

Package	Base Coverage	New Coverage	Difference
dio/lib/src/dio_mixin.dart	🟢 94.12%	🟢 94.25%	🟢 0.13%
Overall Coverage	🟢 85.68%	🟢 85.72%	🟢 0.04%

Minimum allowed coverage is 0%, this run produced 85.72%