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

src/universal/uuid.ts

@@ -1,10 +1,8 @@
 /**
  * Universal UUID implementation
- * Works in all environments: Browser, Node.js, Serverless
+ * Framework-friendly: Works in all environments
  */
 
-import { isBrowser, isNode } from '../utils/environment.js'
-
 export function v4(): string {
   // Use crypto.randomUUID if available (Node.js 19+, modern browsers)
   if (typeof crypto !== 'undefined' && crypto.randomUUID) {