Add stationary object timeout to stop alerts on parked cars

Cars stop being tracked after ~30s stationary (150 frames at 5fps).
Other objects get ~5 minutes (1500 frames) before being dropped.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

argocd/manifests/frigate/configmap.yaml

@@ -30,6 +30,11 @@ data:
               roles: [detect]
         detect:
           enabled: true
+          stationary:
+            max_frames:
+              default: 1500
+              objects:
+                car: 150
         objects:
           track: [person, car, dog, cat, bird]