Audit js.node.test for Node 24 + Haxe 4

[kevinresol]

Summary

• Add missing node:test/reporters externs (js.node.test.Reporters: dot / spec / tap / junit / lcov) for use with Test.run().compose(...).
• Model Test.test as ItFunction (enables test.skip / test.expectFailure like it), typed RunIsolation for run({ isolation }), and document MockTimers Symbol.dispose as an alias of reset().
• Refresh copyright headers to 2014–2026; clarify Node 24 dual-LTS version notes (workerId v24.15, SuiteContext passed/attempt/diagnostic v24.16, attempt v25).

Findings

• Core node:test surface (test/suite/it, hooks, mock, snapshot, assert.register, run options, TestContext / SuiteContext / TestsStream) already matched Node 24 after Add node:test runner externs #214 / Audit observability/test externs for Node 24 + Haxe 4 #225 / Wire Assert, TextEncoder, and MessagePort transfer typing #234.
• Intentionally omitted Current-only APIs: test tags / context.tags / testTagFilters (added in Node v26.2.0).
• Haxe 3 #if haxe4 / js.html.AbortSignal cleanup already on master.
• OpenTelemetry tracing:node.test:* diagnostics channels are docs-only (use existing diagnostics_channel); no new extern needed in this package.

Test plan

• haxe build.hxml (ImportAll) succeeds
• CI matrix on the PR