feat: add telemetry for workflow save and default view (#9734)

Add two new telemetry events: `app:workflow_saved` (with `is_app` and
`is_new` metadata) and `app:default_view_set` for App Builder (with the
chosen view mode). Instrumented in workflowService and
useAppSetDefaultView.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9734-feat-add-telemetry-for-workflow-save-and-default-view-3206d73d3650814e8678f83c8419625f)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/components/builder/useAppSetDefaultView.ts

@@ -43,6 +43,9 @@ export function useAppSetDefaultView() {
     const extra = (app.rootGraph.extra ??= {})
     extra.linearMode = openAsApp
     workflow.changeTracker?.checkState()
+    useTelemetry()?.trackDefaultViewSet({
+      default_view: openAsApp ? 'app' : 'graph'
+    })
     closeDialog()
     showAppliedDialog(openAsApp)
   }