Add Operations - External Process page for vendor processing tracking

Two-tab dashboard tracking external labor workflows (e.g., tin plating):
- Tab 1 "At Vendor": Open POs for outside process items (EXTLAB classcode),
  showing vendor, PO#, finished/manufactured/ext labor PNs, qty, ship date,
  expected return (7-day default), days out, and WO demand
- Tab 2 "Awaiting Shipment": WOs with manufactured material issued but no
  open PO for the outside process item, showing days waiting in stockroom

Nav button added to all 11 pages in Operations section (rows 56-60).

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

application.json

@@ -68,6 +68,10 @@
     {
       "id": "Operations - WO Shortages",
       "isDefault": false
+    },
+    {
+      "id": "Operations - External Process",
+      "isDefault": false
     }
   ],
   "unpublishedAppLayout": {