chore(showcase): remove unused QA-to-Notion sync workflow and script

Author: jpr5

.github/workflows/showcase_qa-sync.yml

@@ -10,8 +10,6 @@
     "validate-manifests": "tsx generate-registry.ts --validate-only",
     "showcase:audit": "tsx audit.ts",
     "create-integration": "tsx create-integration/index.ts",
-    "sync-qa": "tsx sync-qa-to-notion.ts",
-    "sync-qa:dry": "DRY_RUN=true tsx sync-qa-to-notion.ts",
     "bundle-content": "tsx bundle-demo-content.ts",
     "bundle-setup-content": "tsx bundle-setup-content.ts",
     "extract-starter": "tsx extract-starter.ts",