fix(request): default QUERY to idempotent

[ronag]

Summary

• port the applicable RFC 10008 behavior from upstream feat: support HTTP QUERY method (RFC 10008) nodejs/undici#5459
• make QUERY idempotent by default alongside GET and HEAD
• preserve an explicit idempotent: false override
• prove the default can pipeline beside an in-flight request while the explicit override remains queued

Rebased onto current master after the Blob metadata and header snapshot hardening landed.

Validation

• QUERY and complete client-pipelining regressions: 18/18 passed
• Node 26.5.0 with @types/node 26.1.1 declaration/type tests passed
• ESLint and git diff --check passed

[Copilot]

Pull request overview

This PR updates Undici’s core Request construction so the RFC 10008 QUERY method is treated as idempotent by default (like GET/HEAD), enabling HTTP/1.1 pipelining unless the caller explicitly sets idempotent: false.

Changes:

• Default Request#idempotent to true for method: 'QUERY' when idempotent is not provided.
• Add client-level tests proving QUERY pipelines by default, and remains queued when explicitly overridden with idempotent: false.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
test/client-query-idempotence.js	Adds coverage for default pipelining behavior of QUERY vs. explicit idempotent: false queuing.
lib/core/request.js	Extends default idempotency detection to include QUERY.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.