fix(ios): mark generated Watch companion as WKWatchKitApp so Simulator can install it

Reproduction

1. Generate a Craft iOS app with watch.enabled: true.
2. Build the generated iOS app successfully.
3. Run xcrun simctl install <booted-device-id> <app>.app.

Actual result

Installation fails before launch:

Found WatchKit 2.0 app at .../WildLoop.app/Watch/WildLoopWatch.app but it does not have a WKWatchKitApp or WKApplication key set to true in its Info.plist

The generated WatchApp/Info.plist contains WKCompanionAppBundleIdentifier, but no WKWatchKitApp boolean.

Expected result

Craft should emit the required WatchKit marker in the generated Watch app Info.plist so an app embedding the companion installs on iOS Simulator and devices.

Environment

• Craft revision: 26d927f7f927e4db2c85c3df89368d3f3b745dba
• Xcode / iOS SDK: 26.6 / iPhoneSimulator 26.5
• Generated app: WildLoop

This is distinct from #193, which addresses missing WCSessionDelegate methods at compile time.