Add Backup & Restore page (zip download + drag-drop upload)

package-lock.json

@@ -24,6 +24,7 @@
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
         "date-fns": "^3.6.0",
+        "fflate": "^0.8.3",
         "lucide-react": "^0.441.0",
         "next": "14.2.29",
         "next-auth": "^4.24.11",
@@ -4853,6 +4854,12 @@
         "reusify": "^1.0.4"
       }
     },
+    "node_modules/fflate": {
+      "version": "0.8.3",
+      "resolved": "https://registry.npmjs.org/fflate/-/fflate-0.8.3.tgz",
+      "integrity": "sha512-tbZNuJrLwGUp3zshBtdy4W+ORxZuIh8a5ilyIEQDC5rY1f3U20JMry0Ll3WBzU58EZKsEuJFXhb5gwv8CsPvgA==",
+      "license": "MIT"
+    },
     "node_modules/file-entry-cache": {
       "version": "6.0.1",
       "resolved": "https://registry.npmjs.org/file-entry-cache/-/file-entry-cache-6.0.1.tgz",