fly: switch health checks to /nginx-health and extend grace; use [[vm]] with 4x shared, 8GB

Author: andrewm4894

fly.toml

@@ -77,6 +77,6 @@ primary_region = "ord"  # Chicago - you can change this to your preferred region
     port = 80
     type = "http"
     interval = "30s"
-    timeout = "5s"
-    path = "/health"
-    grace_period = "10s"
+    timeout = "10s"
+    path = "/nginx-health"  # temporarily use nginx-level health to avoid startup race
+    grace_period = "60s"     # allow extra time for app services to initialize