feat(quotes): add is_no_quote boolean to schema

Required to mark a quote as an official decline letter. Gates relax
when set so operators can send a quote with zero prices on letterhead.
Field added to PB admin manually (UI-only change per AGENTS.md).

pb-exports/pb_schema-2.json

@@ -2172,6 +2172,16 @@
         "system": false,
         "type": "bool"
       },
+      {
+        "help": "True if this quote is being sent as a 'we cannot quote' decline letter. When set, pricing gates relax and the PDF renders items with 'Not quoted' labels.",
+        "hidden": false,
+        "id": "bool_is_no_quote",
+        "name": "is_no_quote",
+        "presentable": false,
+        "required": false,
+        "system": false,
+        "type": "bool"
+      },
       {
         "cascadeDelete": false,
         "collectionId": "pbc_2527524235",