Harden architecture hot paths

packages/engine/src/task-completion.ts

@@ -0,0 +1,16 @@
+import { getTaskCompletionBlocker, type Task, type TaskStore } from "@fusion/core";
+
+export async function getTaskCompletionBlockerForStore(
+  store: Pick<TaskStore, "getTask">,
+  task: Task,
+): Promise<string | undefined> {
+  return getTaskCompletionBlocker(task, {
+    resolveTask: async (dependencyId) => {
+      try {
+        return await store.getTask(dependencyId);
+      } catch {
+        return null;
+      }
+    },
+  });
+}