test(server): add node --test harness with failing free-tier billing tests

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/package.json

@@ -8,18 +8,18 @@
     "rebuild:batches": "node scripts/rebuild-from-batches.js",
     "diagnostics": "node scripts/plant-diagnostics.js",
     "images:download": "node scripts/download-plant-images.js",
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "node --test test/"
   },
   "keywords": [],
   "author": "",
   "license": "ISC",
-  "dependencies": {
-    "cors": "^2.8.6",
-    "dotenv": "^17.3.1",
-    "express": "^5.2.1",
-    "minio": "^8.0.5",
-    "pg": "^8.16.3",
-    "sharp": "^0.34.5",
-    "stripe": "^20.3.1"
-  }
-}
+  "dependencies": {
+    "cors": "^2.8.6",
+    "dotenv": "^17.3.1",
+    "express": "^5.2.1",
+    "minio": "^8.0.5",
+    "pg": "^8.16.3",
+    "sharp": "^0.34.5",
+    "stripe": "^20.3.1"
+  }
+}