test: reduce brittle assertions and test-only runtime paths (#9289)

* test: focus assertions on behavioral evidence

Prune redundant and wording-coupled checks while retaining diagnostic, parser, recovery, and cleanup coverage.

* refactor: remove test-only wrappers and duplicate checks

Exercise production operations through test fixtures, remove unused adapters, and keep managed-member uncertainty guidance under its existing owner.

* test: focus process validation on diagnostic facts

* refactor: remove test-only runtime helpers

Move semantic evidence fixture setup out of runtime and remove unused Windows settle recovery helpers while checking configured defaults independently.

* test: focus artifact diagnostics on format facts

* test: verify retained cleanup guidance delivery

src/artifacts/bun/BunModuleGraphLayout.ts

@@ -124,17 +124,6 @@ interface SectionWindow {
   readonly truncated: boolean;
 }
 
-/** Probe, then read the one claimed payload. */
-export const locateBunStandaloneGraph = async (
-  handle: FileHandle,
-  fileSize: number,
-  signal?: AbortSignal,
-): Promise<BunStandaloneRecognition> => {
-  const probed = await probeBunStandaloneGraph(handle, fileSize, signal);
-  if (probed.status === "absent" || probed.claim === undefined) return probed;
-  return loadBunStandaloneGraph(handle, probed.claim, signal);
-};
-
 /**
  * Locate at most one graph claim with bounded reads of headers, length
  * prefixes, and suffixes. Payload data is not read. Multiple real claims are