feat: data import module and payment fixes

- Add import module with CSV/Excel template download and bulk import endpoints
- Support client+subscription and outstanding invoice imports with per-row error handling
- Templates include Field Guide sheet with valid plan/area names
- Add manager role to unremitted payments endpoint
- Add createdAt field to remittance history response

package.json

@@ -1,7 +1,9 @@
 {
   "name": "fiberops-api",
   "private": true,
-  "workspaces": ["packages/*"],
+  "workspaces": [
+    "packages/*"
+  ],
   "scripts": {
     "dev": "nest start --watch",
     "build": "nest build",
@@ -32,6 +34,7 @@
     "passport-jwt": "^4.0.1",
     "reflect-metadata": "^0.2.0",
     "rxjs": "^7.8.1",
+    "xlsx": "^0.18.5",
     "zod": "^3.24.0"
   },
   "devDependencies": {