Log every entry and exit of the ordering sync

Neither the success nor the failure line appeared, and save() reports no
expressions at all -- so the function is either not being called or leaving
by a path that says nothing. Two of its exits were silent: the no-viewer
guard, and the case where the computed expressions already match what is
applied.

Logs on entry, logs the inputs it actually saw (the version it resolved, its
bucket_order, how many log entries carry a seq, and what it decided to
build), and logs every exit. One reload should end the guessing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

ui/src/views/Forecast.jsx

@@ -796,7 +796,14 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
       // `expressions` wholesale, so expressions applied earlier were being wiped
       // by the very next line and the ordering columns never appeared in the
       // column list.
-      await syncOrderExpressions()
+      try {
+        await syncOrderExpressions()
+      } catch (err) {
+        // Its own try covers only restore(); save() and the builders sit outside
+        // it, and a throw there would abort the rest of initViewer silently.
+        console.error('[pf-order] threw', err)
+        flash(`Column ordering failed: ${err.message || err}`, 'error')
+      }
 
       if (viewer._pspUpdate) viewer.removeEventListener('perspective-config-update', viewer._pspUpdate)
       viewer._pspUpdate = async () => {