fix(trpc): map v2 field update coordinates to service names

- ZUpdateEnvelopeFieldsRequestSchema accepts page/positionX/positionY but the service consumes
  pageNumber/pageX/pageY, so position updates via POST /envelope/field/update-many were
  silently dropped; map the names in the route before calling updateEnvelopeFields
- docs: show Decimal coordinates as serialized strings in field responses
- docs: include the defaulted fieldMeta values returned when the request omits fieldMeta
- docs: use real envelope/envelope-item ID formats in samples

packages/trpc/server/envelope-router/envelope-fields/update-envelope-fields.ts

@@ -29,7 +29,17 @@ export const updateEnvelopeFieldsRoute = authenticatedProcedure
         id: envelopeId,
       },
       type: null,
-      fields,
+      fields: fields.map((field) => ({
+        id: field.id,
+        type: field.type,
+        pageNumber: field.page,
+        pageX: field.positionX,
+        pageY: field.positionY,
+        width: field.width,
+        height: field.height,
+        fieldMeta: field.fieldMeta,
+        envelopeItemId: field.envelopeItemId,
+      })),
       requestMetadata: ctx.metadata,
     });