feat: add init command to scaffold config and example test

[krismuhi]

Summary

• Adds mobilewright init CLI command that copies pre-bundled template files into the user's project directory
• Ships mobilewright.config.ts and example.test.ts as static templates inside the npm package (templates/ dir)
• Skips files that already exist to avoid clobbering existing work
• Added "templates" to the files array in package.json so the directory is included in the published package

Usage

npx mobilewright init
# created  mobilewright.config.ts
# created  example.test.ts

Test plan

• Run mobilewright init in an empty directory — both files are created
• Run mobilewright init again — both files report skipped (already exists)
• Verify mobilewright.config.ts matches the config example in the docs
• Verify example.test.ts runs without errors against a connected device