Add Operations - WO Shortages page with MTS/MTO shortage tracking

Automates the production manager's manual workflow of checking xTuple WO
Schedule + Kit Material Shortage for FA department work orders. Two tabs:
WO Shortages (detail per WO + shortage line with customer name, YYYY-MM-DD
dates) and Critical Parts (aggregated parts blocking near-term shipments
with QOH from MPE warehouse). Nav button added to all pages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pages/Pending POs/Pending POs.json

@@ -30,4 +30,4 @@
     "name": "Pending POs",
     "slug": "pending-pos-all"
   }
-}
+}