CRAP: platform-apple core (launch diagnostics, CoreDevice, install artifact)

Purpose

Burn down part of the coverage-based CRAP list from #3414.

Function	CRAP	CC	Coverage
`packages/platform-apple/src/core/launch-diagnostics.ts:31` probeSimulatorLaunchContext	56	7	0%
`packages/platform-apple/src/core/physical-device-coredevice.ts:95` normalizeCoreDeviceProbeError	56	7	0%
`packages/platform-apple/src/core/physical-device-coredevice.ts:86` normalizeCoreDeviceReadyError	42	6	0%
`packages/platform-apple/src/core/physical-device-files.ts:8` copyCoreDeviceRunnerFile	30	5	0%
`packages/platform-apple/src/core/install-artifact.ts:210` resolveIosPayloadBundleByHint	30	5	0%

All at 0%. Most are error normalization and diagnostics, so table-driven tests over their inputs should clear them.

Every function above is absent from pnpm check:coverage-crap --all on the PR head (score < 30), or is exempted where this issue says so.
Tests go through the owning module's public entry point. No new production exports for tests and no test-only DI (docs/agents/testing.md).
Only the owned files, the tests that exercise them, and *.fixtures.ts helpers change. The PR stays under the 1,000-line gross budget, and pnpm check:affected --run passes on the pushed head.

Part of #3414.

test(platform-apple): cover core launch diagnostics, CoreDevice norma…