fix: resolve linting issues in check modules
- Fixed checkHandles.ts: removed require-await, added void for floating promises, fixed template literals, removed non-null assertions
- Fixed checkPosts.ts: removed unused imports, added void for floating promises, fixed template literals, removed non-null assertions
- Fixed checkStarterPack.ts: added correct imports for STARTERPACK_CHECKS, fixed floating promises, template literals, and logic issues
All three check modules now have zero linting errors and follow TypeScript best practices.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>