fix(replay): Improve error messages when compression worker fails to load

Previously, when the compression worker failed to load (e.g., due to CSP
restrictions, network issues), Sentry captured a generic ErrorEvent with
almost no useful information ("Event: Event `Event` (type=error)").

This change wraps worker errors in descriptive Error objects that explain
what failed and common causes, making debugging significantly easier.

Fixes JAVASCRIPT-337J

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: billyvg

packages/replay-internal/src/eventBuffer/WorkerHandler.ts

@@ -33,7 +33,8 @@ export class WorkerHandler {
           if ((data as WorkerResponse).success) {
             resolve();
           } else {
-            reject();
+            DEBUG_BUILD && debug.warn('Received worker message w/ unsuccessful status', data);
+            reject(new Error('Received worker message w/ unsuccessful status'));
           }
         },
         { once: true },
@@ -42,7 +43,12 @@ export class WorkerHandler {
       this._worker.addEventListener(
         'error',
         error => {
-          reject(error);
+          DEBUG_BUILD && debug.warn('Failed to load Replay compression worker', error);
+          reject(
+            new Error(
+              `Failed to load Replay compression worker: ${error instanceof ErrorEvent && error.message ? error.message : 'Unknown error. This can happen due to CSP policy restrictions, network issues, or the worker script failing to load.'}`,
+            ),
+          );
         },
         { once: true },
       );