chore(triggers): align the package version and fix the README example

The package was left at 0.3.37 while every other workspace is 0.3.38.
Dependents use `workspace:*`, so no lockfile change is needed.

The "Driving a workflow" example imported the package for its side effect only,
then used `IntervalTrigger` and `PollingTrigger` — copying it produced two
ReferenceErrors. Named imports patch `Workflow.prototype` just the same.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PDvMMv78PuEw4T5atLeJeS

Author: claude

packages/triggers/README.md

@@ -32,7 +32,7 @@ await trigger.stop();
 ## Driving a workflow
 
 ```ts
-import "@workglow/triggers"; // patches Workflow.prototype
+import { IntervalTrigger, PollingTrigger } from "@workglow/triggers"; // also patches Workflow.prototype
 import { Workflow } from "@workglow/task-graph";
 
 const workflow = new Workflow().addTask(MyTask);

packages/triggers/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@workglow/triggers",
   "type": "module",
-  "version": "0.3.37",
+  "version": "0.3.38",
   "repository": {
     "type": "git",
     "url": "https://github.com/workglow-dev/libs.git",