workflow: rename dsh-workflow-vm to dsh-workflow-workerthread

Pure mechanical rename now that the package's internals are the
worker-thread engine: directory, package name, spec/e2e filenames,
module tags and logger prefixes, tsconfig/knip/run-gates/AGENTS.md
references, example cordis.yml plugin ids, doc links; catalogs
regenerated and the lockfile refreshed.

packages/workflow/workflow-workerthread/src/worker.ts

@@ -0,0 +1,18 @@
+/**
+ * The worker-thread entry the engine spawns: bootstrap ./session.ts on the
+ * real `parentPort`. Deliberately a single statement — every piece of logic
+ * lives in `runWorkerSession`, which the unit suite drives in-process over a
+ * `MessageChannel` (code inside a real Worker is invisible to main-process
+ * coverage); loading this module on the main thread throws via
+ * `requireParentPort`, which is how the suite covers the file itself.
+ *
+ * @module @deepseek-ai/dsh-workflow-workerthread/worker
+ */
+
+import { parentPort, workerData } from 'node:worker_threads'
+import { requireParentPort, runWorkerSession } from './session.ts'
+import type { WorkerInit } from './types.ts'
+
+// workerData is `any` at the node:worker_threads boundary; the engine is the
+// only spawner and always provides a WorkerInit.
+void runWorkerSession(requireParentPort(parentPort), workerData as WorkerInit)