feat: CSV import preview/apply endpoints and helpers

backend/package-lock.json

@@ -9,6 +9,7 @@
       "version": "1.0.0",
       "dependencies": {
         "cors": "^2.8.5",
+        "csv-parse": "^6.2.0",
         "express": "^4.18.2",
         "express-rate-limit": "^6.8.0",
         "helmet": "^6.0.1",
@@ -299,6 +300,12 @@
         "url": "https://opencollective.com/express"
       }
     },
+    "node_modules/csv-parse": {
+      "version": "6.2.0",
+      "resolved": "https://registry.npmjs.org/csv-parse/-/csv-parse-6.2.0.tgz",
+      "integrity": "sha512-Zv8KRHccD1q3BJlK4VcQiEn/+suOOp++89g/fpqOxB2U2tU66uC3yM+ZwU6nQQEJp8AqBIiNqB+pUTKNz4QzKg==",
+      "license": "MIT"
+    },
     "node_modules/debug": {
       "version": "2.6.9",
       "resolved": "https://registry.npmjs.org/debug/-/debug-2.6.9.tgz",