fix(ci): build audience-core before SDK bundle in CDN deploy workflow (AUD-239)

The deploy workflow was calling pnpm --filter @imtbl/audience build without
first building its local workspace dependency @imtbl/audience-core, causing
esbuild to fail with "Could not resolve @imtbl/audience-core" because the
dist/ folder did not exist in CI.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: nattb8

.github/workflows/deploy-audience-cdn.yaml

@@ -32,6 +32,9 @@ jobs:
       - name: setup
         uses: ./.github/actions/setup
 
+      - name: Build audience-core
+        run: pnpm --filter @imtbl/audience-core build
+
       - name: Build audience SDK bundle
         run: pnpm --filter @imtbl/audience build