feat: enhance framework integration and simplify codebase

- Simplify universal modules to be more framework-friendly
- Add comprehensive framework integration documentation (Next.js, Vue, React)
- Implement missing relateMany() batch relationship creation method
- Clean up obsolete test files and improve test coverage
- Reduce browser polyfill complexity while maintaining compatibility
- Remove unused browserFramework entry points for cleaner API surface

📄 3,120 lines added, 3,679 lines removed for net simplification

tests/unit/brainy/batch-operations.test.ts

@@ -623,3 +623,4 @@ describe('Brainy Batch Operations', () => {
       }
     })
   })
+})