Desktop app iOS Simulator helper (claude-ios-sim) crash-loops on macOS 27.0: NSInvalidArgumentException in Metal binary archive during CIContext creation

# claude-ios-sim crash-loops on macOS 27.0 when capturing the simulator

**Environment**
- Claude desktop app (Code tab), iOS Simulator panel
- macOS 27.0 (26A428), Xcode 27.0 (27A266a), Apple Silicon
- Simulator runtimes iOS 26.3 / 26.4; booted device iPhone 18 Pro Max

**Symptom**
"Attach a simulator" panel shows "Claude Code iOS Simulator is restarting after a crash. Try again in 1s" in a loop.
`control(attach)` succeeds; the first `control(screenshot)` (or the panel's own frame capture) crashes the helper.
16 crash reports between 11:32 and 11:45 local time.

**Crash**
`~/Library/Logs/DiagnosticReports/claude-ios-sim-2026-09-15-114526.ips`
- SIGABRT, uncaught `NSInvalidArgumentException`:
`*** -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]`
- Last exception backtrace (top → bottom):
```
CoreFoundation -[__NSPlaceholderArray initWithObjects:count:]
Metal __39-[_MTLDevice recordBinaryArchiveUsage:]_block_invoke (dispatch_once)
Metal -[_MTLBinaryArchive loadFromURL:error:]
CoreImage +[CIKernelLibrary(Internal) internalBinaryArchiveWithName:device:]
CoreImage CI::MetalContext::init
CoreImage +[CIContext contextWithMTLDevice:options:]
claude-ios-sim (screenshot / frame pipeline)
```

**Notes**
- Reproduces on every attach; not device-specific (happened after the device set was recreated).
- Headless `xcodebuild` builds/tests on the same simulators work fine; only the panel/screenshot path is affected.
- Likely a macOS 27 Metal/CoreImage regression hit when the helper creates a `CIContext` backed by a Metal device. A software/CPU `CIContext` fallback, or catching the ObjC exception around context creation, would keep the panel usable.

Start at the control(attach) and control(screenshot) paths and the screenshot/frame pipeline where CIContext creation occurs. Reproduce on macOS 27.0 with the listed iOS Simulator setup, then inspect the crash report's Metal/CoreImage trace and compare the available context-creation fallback options. Done means the first screenshot and the panel's frame capture no longer crash-loop the helper.

Written by the indexing model from the issue text.