DBC22-6513: fix camera list south-to-north highway ordering

Reverse Hwy 19/19A/99A route geometries so cameras sort south to
north, and compare route_order numerically in the camera list.

Author: ray-oxd

src/backend/apps/webcam/tasks.py

@@ -520,11 +520,11 @@ def build_route_geometries(coords=hwy_coords):
             points_list = [Point(p) for p in response.json()['route']]
             ls_routes.append(LineString(points_list))
 
-        # DBC22-2456
+        # DBC22-2456 / DBC22-6513: reverse so camera order is south→north (and west→east)
         highways_to_reverse = [
-            '2', '3B', '9', '11', '13', '15', '17A', '23',
+            '2', '3B', '9', '11', '13', '15', '17A', '19', '19A', '23',
             '27', '29', '31', '33', '35', '37', '43', '91A',
-            '93', '95', '97', '97C'
+            '93', '95', '97', '97C', '99A'
         ]
 
         if key in highways_to_reverse:

src/frontend/src/pages/CamerasListPage.js

@@ -222,7 +222,8 @@ export default function CamerasListPage() {
       } else {
         const highwayCompare = collator.compare(a.highway_display, b.highway_display);
         if (highwayCompare == 0) {
-          return collator.compare(a.route_order, b.route_order);
+          // Numeric compare — Collator stringifies null/undefined unpredictably
+          return (a.route_order ?? Number.MAX_SAFE_INTEGER) - (b.route_order ?? Number.MAX_SAFE_INTEGER);
         }
 
         return highwayCompare;

src/frontend/src/pages/SavedCamerasPage.js

@@ -116,7 +116,8 @@ export default function SavedCamerasPage() {
         // Sort by highway first, then default highway/route order
         const highwayCompare = collator.compare(a.highway_display, b.highway_display);
         if (highwayCompare == 0) {
-          return collator.compare(a.route_order, b.route_order);
+          // Numeric compare — Collator stringifies null/undefined unpredictably
+          return (a.route_order ?? Number.MAX_SAFE_INTEGER) - (b.route_order ?? Number.MAX_SAFE_INTEGER);
         }
 
         return highwayCompare;