Fix TypeScript warnings: add explanatory comments to @ts-expect-error directives

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

TextEncodingFactory.ts

@@ -117,18 +117,18 @@ export function createTextDecoder(label?: string, options?: TextDecoderOptions):
 export function installTextEncodingPolyfills(): void {
   const logger = new LoggerComponent('TextEncodingPolyfills');
   
-  // @ts-expect-error
+  // @ts-expect-error - global object access in React Native/Node environment
   if (typeof global !== 'undefined') {
-    // @ts-expect-error
+    // @ts-expect-error - TextEncoder may not exist in global scope
     if (typeof global.TextEncoder === 'undefined') {
-      // @ts-expect-error
+      // @ts-expect-error - Adding to global object
       global.TextEncoder = TextEncoderPolyfill;
       logger.info('Installed TextEncoder polyfill globally');
     }
 
-    // @ts-expect-error
+    // @ts-expect-error - TextDecoder may not exist in global scope
     if (typeof global.TextDecoder === 'undefined') {
-      // @ts-expect-error
+      // @ts-expect-error - Adding to global object
       global.TextDecoder = TextDecoderPolyfill;
       logger.info('Installed TextDecoder polyfill globally');
     }