#3435 test(platform-apple): cover macOS host app discovery and xctestrun product collectors

Summary

Burns down the four coverage-based CRAP findings in #3418 (all were at 0%). Tests drive the owning modules' public entry points only: createLocalAppleMacOsHostProvider's listApps through its own executor and plist-reader arguments (the host-file stat seam declares which app roots exist), and resolveExistingXctestrunProductPaths with the runner test host serving the parsed plist and real product trees on disk. No production exports, no DI, no gate/baseline changes.

Before → after CRAP (issue 5f84627d8 → this head):

Function	Before	After
host-provider.ts listLocalMacApps	42	6
host-provider.ts readMacOsBundleInfo	42	6
runner-xctestrun-products.ts collectXctestrunProductReferenceValuesFromTarget	56	7
runner-xctestrun-products.ts collectConfiguredTestTargets	30	5

Closes #3418. Part of #3414.

Validation

• Tested commit: 740dfbea6.
• pnpm check:affected --run passed on that exact head (all runnable checks; layering, fallow, related tests).
• pnpm check:coverage-crap --all over per-file coverage for both owned files: no function at or above 30 in them (numbers above; both files at 100% function coverage).
• pnpm lint, pnpm typecheck, repo-wide pnpm format --check clean.
• CI Coverage/Integration jobs on this head will confirm the CRAP step; not yet run locally as full gate beyond check:affected.