Add project validation for Watch app and App Clip embedding

[EvanBacon]

Summary

• Adds validateProject() function to detect common App Store submission issues before upload
• Catches Watch app embedding errors that cause "The bundle is not contained in a correctly named directory. It should be under Watch."
• Also validates App Clip embedding configuration
• Fixes AnyBuildPhase export to use export type since it's a type alias

Validation Checks

Code	Description
WATCH_EMBED_MISSING	No "Embed Watch Content" build phase in main target
WATCH_EMBED_WRONG_PATH	dstPath is not $(CONTENTS_FOLDER_PATH)/Watch
WATCH_EMBED_WRONG_SUBFOLDER	dstSubfolderSpec is not 16 (Products Directory)
WATCH_NOT_IN_EMBED	Watch app product not in embed phase files
APPCLIP_EMBED_*	Same checks for App Clips

Usage

import { XcodeProject, validateProject } from '@bacons/xcode';

const project = XcodeProject.open('path/to/project.pbxproj');
const issues = validateProject(project);

for (const issue of issues) {
  console.log(`[${issue.severity}] ${issue.code}: ${issue.message}`);
}

Test plan

• Added validation tests for watch app embedding
• Tests pass with bun test
• Full test suite passes (620 tests)

🤖 Generated with Claude Code