feat(src/brainyData, src/utils): enhance embedding efficiency with batch processing and initialize safeguards

- Added batch embedding support with `defaultBatchEmbeddingFunction`, leveraging shared model instances for optimized performance.
- Integrated `isInitializing` flag to prevent recursive initialization and ensure smooth concurrent operation handling during `BrainyData` initialization.
- Pre-loaded Universal Sentence Encoder in `BrainyData` to prevent delays during embedding.
- Introduced fallback mechanisms in embedding initialization for better error resiliency and model reusability.
- Updated `addBatch` with support for batchSize and refactored text/vector processing logic for clearer separation and memory management.
- Improved GPU and CPU backend selection in Universal Sentence Encoder for compatibility across environments.
- Enhanced memory management by cleaning tensors after embedding operations.
- Updated README with instructions for batch embedding, threading updates, and GPU/CPU optimizations.

src/global.d.ts

@@ -5,11 +5,16 @@
 // Extend the globalThis interface to include the __ENV__ property
 declare global {
   var __ENV__: {
-    isBrowser: boolean;
-    isNode: string | false;
-    isServerless: boolean;
-  };
+    isBrowser: boolean
+    isNode: string | false
+    isServerless: boolean
+  }
+
+  // Window interface extensions (worker-specific functions removed)
+  interface Window {
+    importTensorFlow?: () => Promise<any>
+  }
 }
 
 // This export is needed to make this file a module
-export {};
+export {}