test: label native browser transport failures

tests/helpers/browser-operation.tsadded+25-0

Changes to tests/helpers/browser-operation.ts

		@@ -0,0 +1,25 @@
	1	+import { writeSync } from 'node:fs'
	2	+
	3	+export type BrowserControlAction = 'status' | 'release' | 'verify' | 'read-only' | 'revoke'
	4	+type BrowserOperation = 'version-fetch' | 'version-json' | 'browser-socket' | 'target-fetch' | 'target-json' | 'page-socket' | `control-${BrowserControlAction}-${'fetch' | 'json'}`
	5	+
	6	+/** Observe an owned transport boundary without replacing its result, error or timeout. */
	7	+export async function observeBrowserOperation<T>(operation: BrowserOperation, work: () => Promise<T>): Promise<T> {
	8	+ const began = performance.now()
	9	+ try { return await work() }
	10	+ catch (error) {
	11	+ // Reporting is best effort. A closed diagnostic pipe must preserve the native error.
	12	+ try {
	13	+ const phase = operation.startsWith('version-') || operation === 'browser-socket' ? 'browser-start' : operation.startsWith('control-') ? 'workspace-control' : 'page-open'
	14	+ const nativeError = error instanceof Error && ['TimeoutError', 'AbortError', 'SyntaxError'].includes(error.name) ? error.name : 'other'
	15	+ const bytes = new TextEncoder().encode(`${JSON.stringify({ oracle: 'browser-operation-failure', phase, operation, nativeError, elapsedMs: performance.now() - began })}\n`)
	16	+ const report = (descriptor: number) => {
	17	+ try { return writeSync(descriptor, bytes) === bytes.byteLength }
	18	+ catch { return false }
	19	+ }
	20	+ if (!report(2)) report(1)
	21	+ }
	22	+ catch {}
	23	+ throw error
	24	+ }
	25	+}