fix: improve code quality, type safety, and documentation - #4971

Code Quality Improvements:
- Replace `any` types with `unknown` in error handling (index.ts, processor.ts)
- Fix type safety in provider.ts by using proper type assertions
- Fix plugin hook typing to avoid @ts-expect-error
- Fix fetch type compatibility in plugin/index.ts
- Remove unused debug file (util/scrap.ts)
- Replace console.log with UI.println in stats.ts for consistent output

Test Improvements:
- Enable permission boundary test in patch.test.ts
- Enable directory traversal test in bash.test.ts
- Use polling pattern instead of arbitrary setTimeout for async tests

Documentation:
- Redesigned README with better structure and formatting
- Added feature highlights section
- Added installation table for easier reference
- Added agents comparison table
- Added collapsible FAQ sections
- Added configuration section
- Improved community links with badges