chore(audience): post-rebase cleanup for main drift

After rebasing feat/audience-web-sdk-demo onto main, four places still
referenced the pre-review shape of AudienceError that #2841 changed
during review, plus the lockfile carried stale resolutions from before
main drifted:

- src/cdn.ts: AudienceError now lives in @imtbl/audience-core/errors,
  not sdk/src/types. Import it from core alongside IdentityType.
- README.md: the AudienceError.code union lost 'UNKNOWN' and gained
  'VALIDATION_REJECTED' (terminal failure, 2xx with rejected > 0).
  Update the documented shape to match.
- src/cdn.test.ts: the smoke test's fake AudienceError was constructed
  with code: 'UNKNOWN', which is no longer a valid AudienceErrorCode.
  Use 'NETWORK_ERROR' which matches the test's status: 0 setup.
- pnpm-lock.yaml: reset to main's baseline and reinstall so the only
  delta is the new esbuild-plugin-replace dev-dep added by the CDN
  bundle build commit. This avoids the rebase carrying over stale
  @types/node and peer-context resolutions from before main drifted.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ImmutableJeffrey

packages/audience/sdk/README.md

@@ -126,7 +126,7 @@ IdentityType.Passport; // 'passport'
 
 ```ts
 class AudienceError extends Error {
-  readonly code: 'FLUSH_FAILED' | 'CONSENT_SYNC_FAILED' | 'NETWORK_ERROR' | 'UNKNOWN';
+  readonly code: 'FLUSH_FAILED' | 'CONSENT_SYNC_FAILED' | 'NETWORK_ERROR' | 'VALIDATION_REJECTED';
   readonly status: number;          // HTTP status, 0 for network failure
   readonly endpoint: string;        // full URL that failed
   readonly responseBody?: unknown;  // parsed JSON body from the backend

packages/audience/sdk/src/cdn.test.ts

@@ -38,7 +38,7 @@ describe('cdn entry point', () => {
 
     // AudienceError should be constructable and extend Error
     const err = new (g!.AudienceError as any)({
-      code: 'UNKNOWN',
+      code: 'NETWORK_ERROR',
       message: 'test',
       status: 0,
       endpoint: 'https://example.com',

packages/audience/sdk/src/cdn.ts

@@ -10,11 +10,10 @@
  * for the CDN build (packages/audience/sdk/tsup.cdn.js).
  */
 
-import { IdentityType } from '@imtbl/audience-core';
+import { AudienceError, IdentityType } from '@imtbl/audience-core';
 
 import { Audience } from './sdk';
 import { LIBRARY_VERSION } from './config';
-import { AudienceError } from './types';
 
 type GlobalShape = {
   Audience: typeof Audience;