test(dashboard): align github-tracking-documentation phrases with current docs

The doc was rewritten to cover "every task-creation path" (with an
explicit enumeration of surfaces) instead of the older "task creation
flows (including ...)" wording, and uses "best-effort and non-blocking"
instead of "Creation is best-effort and non-blocking". Update the
documentation contract test to match the current phrasing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Fusion-Task-Id: FN-5208

packages/core/src/index.ts

@@ -129,6 +129,7 @@ export {
   SELF_DEFEATING_OPERATION_VERBS,
   detectSelfDefeatingDependency,
   SelfDefeatingDependencyError,
+  TaskDeletedError,
 } from "./store.js";
 export {
   STOPWORDS,