feat(dashboard): bulk import Grok CLI accounts from JSON

Add a "Bulk Add" flow for the grok-cli provider, mirroring the existing
codex one: paste a JSON array/object or drag-drop multiple .json files,
then create all OAuth connections in a single call.

- BulkImportGrokCliModal: flexible JSON parsing (array, single object,
  {accounts:[...]}, concatenated objects) + multi-file upload
- POST /api/oauth/grok-cli/bulk-import: serial createProviderConnection,
  snake_case/camelCase token fields, email backfilled from id_token or
  access_token, authMethod "device_code" to match the login flow

src/app/(dashboard)/dashboard/providers/[id]/page.js

@@ -22,6 +22,7 @@ import AddApiKeyModal from "./AddApiKeyModal";
 import EditCompatibleNodeModal from "./EditCompatibleNodeModal";
 import AddCustomModelModal from "./AddCustomModelModal";
 import BulkImportCodexModal from "./BulkImportCodexModal";
+import BulkImportGrokCliModal from "./BulkImportGrokCliModal";
 
 const ONE_BY_ONE_DELAY_MS = 1000;
 
@@ -48,6 +49,7 @@ export default function ProviderDetailPage() {
   const [showAddApiKeyModal, setShowAddApiKeyModal] = useState(false);
   const [addConnectionError, setAddConnectionError] = useState("");
   const [showBulkImportCodex, setShowBulkImportCodex] = useState(false);
+  const [showBulkImportGrokCli, setShowBulkImportGrokCli] = useState(false);
   const [showEditModal, setShowEditModal] = useState(false);
   const [showEditNodeModal, setShowEditNodeModal] = useState(false);
   const [showBulkProxyModal, setShowBulkProxyModal] = useState(false);
@@ -1529,6 +1531,11 @@ export default function ProviderDetailPage() {
                         {translate("Bulk Add")}
                       </Button>
                     )}
+                    {providerId === "grok-cli" && (
+                      <Button size="sm" icon="playlist_add" variant="secondary" onClick={() => setShowBulkImportGrokCli(true)}>
+                        {translate("Bulk Add")}
+                      </Button>
+                    )}
                     <Button
                       size="sm"
                       icon="add"
@@ -1598,6 +1605,18 @@ export default function ProviderDetailPage() {
                       {translate("Bulk Add")}
                     </Button>
                   )}
+                  {providerId === "grok-cli" && (
+                    <Button
+                      size="sm"
+                      icon="playlist_add"
+                      variant="secondary"
+                      onClick={() => setShowBulkImportGrokCli(true)}
+                      title={translate("Bulk import Grok CLI accounts from JSON")}
+                      className="w-full sm:w-auto"
+                    >
+                      {translate("Bulk Add")}
+                    </Button>
+                  )}
                   {hasDualAuthModes ? (
                     <>
                       <Button
@@ -1778,6 +1797,14 @@ export default function ProviderDetailPage() {
         />
       )}
 
+      {providerId === "grok-cli" && (
+        <BulkImportGrokCliModal
+          isOpen={showBulkImportGrokCli}
+          onClose={() => setShowBulkImportGrokCli(false)}
+          onSuccess={fetchConnections}
+        />
+      )}
+
       {/* AG Risk Confirmation Modal */}
       <ConfirmModal
         isOpen={showAgRiskModal}