Add helpers and prepare for importing them

GitOrigin-RevId: 115c5ba3160a4cc3751ae26c232a85fed6b42baf

package-lock.json

@@ -52043,14 +52043,18 @@
         "@overleaf/logger": "*",
         "@overleaf/metrics": "*",
         "@overleaf/mongo-utils": "*",
+        "@overleaf/o-error": "*",
         "@overleaf/promise-utils": "*",
         "@overleaf/settings": "*",
+        "@overleaf/validation-tools": "*",
         "async": "^3.2.5",
         "body-parser": "^1.20.3",
         "bunyan": "^1.8.15",
         "express": "^4.21.2",
         "method-override": "^3.0.0",
-        "mongodb-legacy": "6.1.3"
+        "mongodb-legacy": "6.1.3",
+        "zod": "^4.1.7",
+        "zod-validation-error": "^4.0.1"
       },
       "devDependencies": {
         "chai-as-promised": "^7.1.1",

services/notifications/package.json

@@ -24,14 +24,18 @@
     "@overleaf/logger": "*",
     "@overleaf/metrics": "*",
     "@overleaf/mongo-utils": "*",
+    "@overleaf/o-error": "*",
     "@overleaf/settings": "*",
     "@overleaf/promise-utils": "*",
+    "@overleaf/validation-tools": "*",
     "async": "^3.2.5",
     "body-parser": "^1.20.3",
     "bunyan": "^1.8.15",
     "express": "^4.21.2",
     "method-override": "^3.0.0",
-    "mongodb-legacy": "6.1.3"
+    "mongodb-legacy": "6.1.3",
+    "zod": "^4.1.7",
+    "zod-validation-error": "^4.0.1"
   },
   "devDependencies": {
     "chai": "^4.3.6",

services/notifications/tsconfig.json

@@ -1,5 +1,8 @@
 {
   "extends": "../../tsconfig.backend.json",
+  "compilerOptions": {
+    "allowImportingTsExtensions": true
+  },
   "include": [
     "app.js",
     "app/js/**/*",