frontend/src/features/settings/README-IMPORT.md

@@ -0,0 +1,91 @@
+# User Data Import Feature
+
+## Overview
+
+Frontend implementation of user data import feature (issue #26, Milestone 4).
+
+## Components
+
+### ImportButton
+**File**: `components/ImportButton.tsx`
+- Opens file selector for .tar.gz files
+- Client-side validation (file extension, size limit 500MB)
+- Triggers ImportDialog on file selection
+
+### ImportDialog
+**File**: `components/ImportDialog.tsx`
+- Multi-step wizard: Upload → Preview → Confirm → Progress → Results
+- Step 1 (Upload): Shows selected file details
+- Step 2 (Preview): Loading state while generating preview
+- Step 3 (Confirm): Displays manifest, conflicts, mode selection (merge/replace)
+- Step 4 (Progress): Shows import in progress
+- Step 5 (Results): Displays summary with counts and any errors/warnings
+- Responsive design for mobile (320px, 768px) and desktop (1920px)
+- Touch targets >= 44px per CLAUDE.md requirement
+
+### API Client
+**File**: `api/import.api.ts`
+- `getPreview(file)`: POST /api/user/import/preview (multipart)
+- `executeImport(file, mode)`: POST /api/user/import (multipart)
+- 2-minute timeout for large files
+
+### React Query Hooks
+**File**: `hooks/useImportUserData.ts`
+- `useImportPreview()`: Mutation for preview generation
+- `useImportUserData()`: Mutation for import execution
+- Toast notifications for success/error states
+
+### Types
+**File**: `types/import.types.ts`
+- `ImportManifest`: Archive contents and metadata
+- `ImportPreview`: Preview data with conflicts
+- `ImportResult`: Import execution results
+- Mirrors backend types from `backend/src/features/user-import/domain/user-import.types.ts`
+
+## Integration
+
+The import button is placed in the Data Management section of the mobile settings screen, directly above the existing export button.
+
+**File**: `mobile/MobileSettingsScreen.tsx`
+- Added ImportButton component
+- Added ImportDialog component
+- Manages file selection and dialog state
+
+## Usage Flow
+
+1. User clicks "Import My Data" button
+2. File selector opens (.tar.gz filter)
+3. User selects export archive
+4. Dialog opens and automatically generates preview
+5. Preview shows counts, conflicts, warnings
+6. User selects mode (merge or replace)
+7. User confirms import
+8. Progress indicator shows during import
+9. Results screen displays summary with counts
+10. User clicks "Done" to close dialog
+
+## Validation
+
+- Client-side: File extension (.tar.gz), size (500MB max)
+- Server-side: MIME type, magic bytes, archive structure, manifest validation
+- User-facing error messages for all failure scenarios
+
+## Responsive Design
+
+- Mobile (320px): Full-width dialog, stacked layout, 44px touch targets
+- Tablet (768px): Centered dialog, readable text
+- Desktop (1920px): Max-width constrained dialog (2xl = 672px)
+
+## Quality Checklist
+
+- [x] Type-check passes
+- [x] Linting passes
+- [x] Mobile viewport support (320px, 768px)
+- [x] Desktop viewport support (1920px)
+- [x] Touch targets >= 44px
+- [x] Error handling with user-friendly messages
+- [x] Loading states for async operations
+- [x] Success/error toast notifications
+- [x] Follows existing export button pattern
+- [x] Material-UI component consistency
+- [x] Dark mode support

frontend/src/features/settings/api/import.api.ts

@@ -0,0 +1,45 @@
+/**
+ * @ai-summary API client for user data import
+ * @ai-context Uploads import archive, generates preview, executes import
+ */
+
+import { apiClient } from '../../../core/api/client';
+import { ImportPreview, ImportResult } from '../types/import.types';
+
+export const importApi = {
+  /**
+   * Generate preview of import data
+   */
+  getPreview: async (file: File): Promise<ImportPreview> => {
+    const formData = new FormData();
+    formData.append('file', file);
+
+    const response = await apiClient.post('/user/import/preview', formData, {
+      headers: {
+        'Content-Type': 'multipart/form-data',
+      },
+      timeout: 120000, // 2 minute timeout for large files
+    });
+    return response.data;
+  },
+
+  /**
+   * Execute import with specified mode
+   */
+  executeImport: async (
+    file: File,
+    mode: 'merge' | 'replace'
+  ): Promise<ImportResult> => {
+    const formData = new FormData();
+    formData.append('file', file);
+    formData.append('mode', mode);
+
+    const response = await apiClient.post('/user/import', formData, {
+      headers: {
+        'Content-Type': 'multipart/form-data',
+      },
+      timeout: 120000, // 2 minute timeout for large imports
+    });
+    return response.data;
+  },
+};

frontend/src/features/settings/components/ImportButton.tsx

@@ -0,0 +1,67 @@
+/**
+ * @ai-summary Import button component
+ * @ai-context Opens file selector and triggers import dialog
+ */
+
+import React, { useRef } from 'react';
+import toast from 'react-hot-toast';
+
+interface ImportButtonProps {
+  onFileSelected: (file: File) => void;
+  disabled?: boolean;
+}
+
+export const ImportButton: React.FC<ImportButtonProps> = ({
+  onFileSelected,
+  disabled = false,
+}) => {
+  const fileInputRef = useRef<HTMLInputElement>(null);
+
+  const handleButtonClick = () => {
+    fileInputRef.current?.click();
+  };
+
+  const handleFileChange = (event: React.ChangeEvent<HTMLInputElement>) => {
+    const file = event.target.files?.[0];
+    if (!file) return;
+
+    // Validate file extension
+    if (!file.name.endsWith('.tar.gz')) {
+      toast.error('Please select a .tar.gz file');
+      return;
+    }
+
+    // Validate file size (max 500MB)
+    const maxSize = 500 * 1024 * 1024;
+    if (file.size > maxSize) {
+      toast.error('File size exceeds 500MB limit');
+      return;
+    }
+
+    onFileSelected(file);
+
+    // Reset input so same file can be selected again
+    event.target.value = '';
+  };
+
+  return (
+    <>
+      <input
+        ref={fileInputRef}
+        type="file"
+        accept=".tar.gz"
+        onChange={handleFileChange}
+        style={{ display: 'none' }}
+        aria-label="Select import file"
+      />
+      <button
+        onClick={handleButtonClick}
+        disabled={disabled}
+        className="w-full text-left p-3 bg-primary-50 text-primary-700 rounded-lg font-medium hover:bg-primary-100 transition-colors disabled:opacity-50 dark:bg-primary-900/20 dark:text-primary-300 dark:hover:bg-primary-900/30"
+        style={{ minHeight: '44px' }}
+      >
+        Import My Data
+      </button>
+    </>
+  );
+};

frontend/src/features/settings/components/ImportDialog.tsx

@@ -0,0 +1,374 @@
+/**
+ * @ai-summary Import dialog component
+ * @ai-context Multi-step dialog: upload -> preview -> confirm -> progress -> results
+ */
+
+import React, { useState, useEffect } from 'react';
+import { useImportPreview, useImportUserData } from '../hooks/useImportUserData';
+import { ImportPreview, ImportResult } from '../types/import.types';
+
+interface ImportDialogProps {
+  isOpen: boolean;
+  onClose: () => void;
+  file: File | null;
+}
+
+type ImportStep = 'upload' | 'preview' | 'confirm' | 'progress' | 'results';
+
+export const ImportDialog: React.FC<ImportDialogProps> = ({
+  isOpen,
+  onClose,
+  file,
+}) => {
+  const [step, setStep] = useState<ImportStep>('upload');
+  const [preview, setPreview] = useState<ImportPreview | null>(null);
+  const [mode, setMode] = useState<'merge' | 'replace'>('merge');
+  const [result, setResult] = useState<ImportResult | null>(null);
+
+  const previewMutation = useImportPreview();
+  const importMutation = useImportUserData();
+
+  const handleGeneratePreview = async () => {
+    if (!file) return;
+
+    setStep('preview');
+    try {
+      const previewData = await previewMutation.mutateAsync(file);
+      setPreview(previewData);
+      setStep('confirm');
+    } catch {
+      // Error handled by mutation hook
+      setStep('upload');
+    }
+  };
+
+  const handleConfirmImport = async () => {
+    if (!file) return;
+
+    setStep('progress');
+    try {
+      const importResult = await importMutation.mutateAsync({ file, mode });
+      setResult(importResult);
+      setStep('results');
+    } catch {
+      // Error handled by mutation hook
+      setStep('confirm');
+    }
+  };
+
+  // Reset state when dialog opens
+  useEffect(() => {
+    if (isOpen && file) {
+      setStep('upload');
+      setPreview(null);
+      setMode('merge');
+      setResult(null);
+      // Automatically start preview generation
+      handleGeneratePreview();
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [isOpen, file]);
+
+  const handleClose = () => {
+    setStep('upload');
+    setPreview(null);
+    setMode('merge');
+    setResult(null);
+    onClose();
+  };
+
+  if (!isOpen) return null;
+
+  const formatBytes = (bytes: number): string => {
+    if (bytes === 0) return '0 Bytes';
+    const k = 1024;
+    const sizes = ['Bytes', 'KB', 'MB', 'GB'];
+    const i = Math.floor(Math.log(bytes) / Math.log(k));
+    return Math.round(bytes / Math.pow(k, i) * 100) / 100 + ' ' + sizes[i];
+  };
+
+  return (
+    <div className="fixed inset-0 bg-black bg-opacity-50 dark:bg-black/70 flex items-center justify-center z-50 p-4">
+      <div className="bg-white dark:bg-scuro rounded-lg p-6 max-w-2xl w-full max-h-[90vh] overflow-y-auto">
+        <h3 className="text-lg font-semibold text-slate-800 dark:text-avus mb-4">
+          Import Data
+        </h3>
+
+        {/* Step 1: Upload */}
+        {step === 'upload' && file && (
+          <div>
+            <p className="text-slate-600 dark:text-titanio mb-4">
+              File selected: {file.name} ({formatBytes(file.size)})
+            </p>
+            <div className="flex justify-end space-x-3 mt-6">
+              <button
+                onClick={handleClose}
+                className="px-4 py-2 bg-gray-200 dark:bg-gray-700 text-gray-700 dark:text-gray-200 rounded-lg font-medium"
+                style={{ minHeight: '44px', minWidth: '44px' }}
+              >
+                Cancel
+              </button>
+            </div>
+          </div>
+        )}
+
+        {/* Step 2: Preview (Loading) */}
+        {step === 'preview' && (
+          <div>
+            <div className="flex flex-col items-center justify-center py-8">
+              <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-primary-500 mb-4"></div>
+              <p className="text-slate-600 dark:text-titanio">
+                Analyzing import file...
+              </p>
+            </div>
+          </div>
+        )}
+
+        {/* Step 3: Confirm */}
+        {step === 'confirm' && preview && (
+          <div>
+            <div className="mb-6">
+              <h4 className="font-semibold text-slate-800 dark:text-avus mb-3">
+                Import Summary
+              </h4>
+              <div className="space-y-2 text-sm">
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">Vehicles:</span>
+                  <span className="font-medium text-slate-800 dark:text-avus">
+                    {preview.manifest.contents.vehicles.count}
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">Fuel Logs:</span>
+                  <span className="font-medium text-slate-800 dark:text-avus">
+                    {preview.manifest.contents.fuelLogs.count}
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">
+                    Maintenance Records:
+                  </span>
+                  <span className="font-medium text-slate-800 dark:text-avus">
+                    {preview.manifest.contents.maintenanceRecords.count}
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">
+                    Maintenance Schedules:
+                  </span>
+                  <span className="font-medium text-slate-800 dark:text-avus">
+                    {preview.manifest.contents.maintenanceSchedules.count}
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">Documents:</span>
+                  <span className="font-medium text-slate-800 dark:text-avus">
+                    {preview.manifest.contents.documents.count}
+                  </span>
+                </div>
+              </div>
+
+              {preview.conflicts.vehicles > 0 && (
+                <div className="mt-4 p-3 bg-yellow-50 dark:bg-yellow-900/20 rounded-lg">
+                  <p className="text-sm text-yellow-800 dark:text-yellow-300">
+                    <strong>Conflicts detected:</strong> {preview.conflicts.vehicles}{' '}
+                    vehicle(s) with matching VINs already exist.
+                  </p>
+                </div>
+              )}
+
+              {preview.manifest.warnings.length > 0 && (
+                <div className="mt-4 p-3 bg-orange-50 dark:bg-orange-900/20 rounded-lg">
+                  <p className="text-sm font-medium text-orange-800 dark:text-orange-300 mb-2">
+                    Warnings:
+                  </p>
+                  <ul className="text-sm text-orange-700 dark:text-orange-400 list-disc list-inside">
+                    {preview.manifest.warnings.map((warning, idx) => (
+                      <li key={idx}>{warning}</li>
+                    ))}
+                  </ul>
+                </div>
+              )}
+            </div>
+
+            <div className="mb-6">
+              <h4 className="font-semibold text-slate-800 dark:text-avus mb-3">
+                Import Mode
+              </h4>
+              <div className="space-y-3">
+                <label className="flex items-start space-x-3 cursor-pointer">
+                  <input
+                    type="radio"
+                    name="mode"
+                    value="merge"
+                    checked={mode === 'merge'}
+                    onChange={() => setMode('merge')}
+                    className="mt-1"
+                    style={{ minWidth: '20px', minHeight: '20px' }}
+                  />
+                  <div className="flex-1">
+                    <p className="font-medium text-slate-800 dark:text-avus">
+                      Merge (Recommended)
+                    </p>
+                    <p className="text-sm text-slate-600 dark:text-titanio">
+                      Keep existing data and add new items. Update matching VINs.
+                    </p>
+                  </div>
+                </label>
+                <label className="flex items-start space-x-3 cursor-pointer">
+                  <input
+                    type="radio"
+                    name="mode"
+                    value="replace"
+                    checked={mode === 'replace'}
+                    onChange={() => setMode('replace')}
+                    className="mt-1"
+                    style={{ minWidth: '20px', minHeight: '20px' }}
+                  />
+                  <div className="flex-1">
+                    <p className="font-medium text-slate-800 dark:text-avus">
+                      Replace All
+                    </p>
+                    <p className="text-sm text-slate-600 dark:text-titanio">
+                      Delete all existing data and replace with imported data.
+                    </p>
+                  </div>
+                </label>
+              </div>
+            </div>
+
+            <div className="flex justify-end space-x-3 mt-6">
+              <button
+                onClick={handleClose}
+                className="px-4 py-2 bg-gray-200 dark:bg-gray-700 text-gray-700 dark:text-gray-200 rounded-lg font-medium"
+                style={{ minHeight: '44px', minWidth: '44px' }}
+              >
+                Cancel
+              </button>
+              <button
+                onClick={handleConfirmImport}
+                className="px-4 py-2 bg-primary-500 text-white rounded-lg font-medium hover:bg-primary-600 transition-colors dark:bg-primary-600 dark:hover:bg-primary-700"
+                style={{ minHeight: '44px', minWidth: '44px' }}
+              >
+                {mode === 'replace' ? 'Replace All Data' : 'Import'}
+              </button>
+            </div>
+          </div>
+        )}
+
+        {/* Step 4: Progress */}
+        {step === 'progress' && (
+          <div>
+            <div className="flex flex-col items-center justify-center py-8">
+              <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-primary-500 mb-4"></div>
+              <p className="text-slate-600 dark:text-titanio">
+                Importing data... This may take a few minutes.
+              </p>
+            </div>
+          </div>
+        )}
+
+        {/* Step 5: Results */}
+        {step === 'results' && result && (
+          <div>
+            <div className="mb-6">
+              <div
+                className={`p-4 rounded-lg mb-4 ${
+                  result.success
+                    ? 'bg-green-50 dark:bg-green-900/20'
+                    : 'bg-red-50 dark:bg-red-900/20'
+                }`}
+              >
+                <p
+                  className={`font-semibold ${
+                    result.success
+                      ? 'text-green-800 dark:text-green-300'
+                      : 'text-red-800 dark:text-red-300'
+                  }`}
+                >
+                  {result.success
+                    ? 'Import completed successfully!'
+                    : 'Import completed with errors'}
+                </p>
+              </div>
+
+              <h4 className="font-semibold text-slate-800 dark:text-avus mb-3">
+                Import Summary
+              </h4>
+              <div className="space-y-2 text-sm">
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">
+                    Mode:
+                  </span>
+                  <span className="font-medium text-slate-800 dark:text-avus capitalize">
+                    {result.mode}
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">
+                    Imported:
+                  </span>
+                  <span className="font-medium text-green-600 dark:text-green-400">
+                    {result.summary.imported}
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">
+                    Updated:
+                  </span>
+                  <span className="font-medium text-blue-600 dark:text-blue-400">
+                    {result.summary.updated}
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600 dark:text-titanio">
+                    Skipped:
+                  </span>
+                  <span className="font-medium text-gray-600 dark:text-gray-400">
+                    {result.summary.skipped}
+                  </span>
+                </div>
+              </div>
+
+              {result.summary.errors.length > 0 && (
+                <div className="mt-4 p-3 bg-red-50 dark:bg-red-900/20 rounded-lg">
+                  <p className="text-sm font-medium text-red-800 dark:text-red-300 mb-2">
+                    Errors:
+                  </p>
+                  <ul className="text-sm text-red-700 dark:text-red-400 list-disc list-inside max-h-40 overflow-y-auto">
+                    {result.summary.errors.map((error, idx) => (
+                      <li key={idx}>{error}</li>
+                    ))}
+                  </ul>
+                </div>
+              )}
+
+              {result.warnings.length > 0 && (
+                <div className="mt-4 p-3 bg-orange-50 dark:bg-orange-900/20 rounded-lg">
+                  <p className="text-sm font-medium text-orange-800 dark:text-orange-300 mb-2">
+                    Warnings:
+                  </p>
+                  <ul className="text-sm text-orange-700 dark:text-orange-400 list-disc list-inside">
+                    {result.warnings.map((warning, idx) => (
+                      <li key={idx}>{warning}</li>
+                    ))}
+                  </ul>
+                </div>
+              )}
+            </div>
+
+            <div className="flex justify-end mt-6">
+              <button
+                onClick={handleClose}
+                className="px-4 py-2 bg-primary-500 text-white rounded-lg font-medium hover:bg-primary-600 transition-colors dark:bg-primary-600 dark:hover:bg-primary-700"
+                style={{ minHeight: '44px', minWidth: '44px' }}
+              >
+                Done
+              </button>
+            </div>
+          </div>
+        )}
+      </div>
+    </div>
+  );
+};

frontend/src/features/settings/hooks/useImportUserData.ts

@@ -0,0 +1,59 @@
+/**
+ * @ai-summary React Query hook for user data import
+ * @ai-context Manages import flow: preview -> execute with mode selection
+ */
+
+import { useMutation } from '@tanstack/react-query';
+import toast from 'react-hot-toast';
+import { importApi } from '../api/import.api';
+import { ImportPreview, ImportResult } from '../types/import.types';
+
+interface ApiError {
+  response?: {
+    data?: {
+      error?: string;
+      message?: string;
+    };
+  };
+  message?: string;
+}
+
+export const useImportPreview = () => {
+  return useMutation<ImportPreview, ApiError, File>({
+    mutationFn: (file: File) => importApi.getPreview(file),
+    onError: (error: ApiError) => {
+      toast.error(
+        error.response?.data?.message ||
+          error.response?.data?.error ||
+          'Failed to generate preview'
+      );
+    },
+  });
+};
+
+export const useImportUserData = () => {
+  return useMutation<
+    ImportResult,
+    ApiError,
+    { file: File; mode: 'merge' | 'replace' }
+  >({
+    mutationFn: ({ file, mode }) => importApi.executeImport(file, mode),
+    onSuccess: (result) => {
+      if (result.success) {
+        const { imported, updated, skipped } = result.summary;
+        toast.success(
+          `Import complete: ${imported} imported, ${updated} updated, ${skipped} skipped`
+        );
+      } else {
+        toast.error('Import completed with errors. Check results for details.');
+      }
+    },
+    onError: (error: ApiError) => {
+      toast.error(
+        error.response?.data?.message ||
+          error.response?.data?.error ||
+          'Failed to import data'
+      );
+    },
+  });
+};

frontend/src/features/settings/mobile/MobileSettingsScreen.tsx

@@ -11,6 +11,8 @@ import { useAdminAccess } from '../../../core/auth/useAdminAccess';
 import { useNavigationStore } from '../../../core/store';
 import { DeleteAccountModal } from './DeleteAccountModal';
 import { PendingDeletionBanner } from './PendingDeletionBanner';
+import { ImportButton } from '../components/ImportButton';
+import { ImportDialog } from '../components/ImportDialog';
 
 interface ToggleSwitchProps {
   enabled: boolean;
@@ -90,6 +92,8 @@ export const MobileSettingsScreen: React.FC = () => {
   const [isEditingProfile, setIsEditingProfile] = useState(false);
   const [editedDisplayName, setEditedDisplayName] = useState('');
   const [editedNotificationEmail, setEditedNotificationEmail] = useState('');
+  const [showImportDialog, setShowImportDialog] = useState(false);
+  const [importFile, setImportFile] = useState<File | null>(null);
 
   // Initialize edit form when profile loads or edit mode starts
   React.useEffect(() => {
@@ -108,6 +112,16 @@ export const MobileSettingsScreen: React.FC = () => {
     exportMutation.mutate();
   };
 
+  const handleImportFileSelected = (file: File) => {
+    setImportFile(file);
+    setShowImportDialog(true);
+  };
+
+  const handleImportDialogClose = () => {
+    setShowImportDialog(false);
+    setImportFile(null);
+  };
+
 
   const handleEditProfile = () => {
     setIsEditingProfile(true);
@@ -439,9 +453,14 @@ export const MobileSettingsScreen: React.FC = () => {
           <div>
             <h2 className="text-lg font-semibold text-slate-800 dark:text-avus mb-4">Data Management</h2>
             <div className="space-y-3">
+              <ImportButton onFileSelected={handleImportFileSelected} />
+              <p className="text-sm text-slate-500 dark:text-titanio">
+                Restore your data from a previous export
+              </p>
               <button
                 onClick={() => setShowDataExport(true)}
                 className="w-full text-left p-3 bg-primary-50 text-primary-700 rounded-lg font-medium hover:bg-primary-100 transition-colors dark:bg-primary-900/20 dark:text-primary-300 dark:hover:bg-primary-900/30"
+                style={{ minHeight: '44px' }}
               >
                 Export My Data
               </button>
@@ -572,6 +591,13 @@ export const MobileSettingsScreen: React.FC = () => {
           isOpen={showDeleteConfirm}
           onClose={() => setShowDeleteConfirm(false)}
         />
+
+        {/* Import Dialog */}
+        <ImportDialog
+          isOpen={showImportDialog}
+          onClose={handleImportDialogClose}
+          file={importFile}
+        />
       </div>
     </MobileContainer>
   );

frontend/src/features/settings/types/import.types.ts

@@ -0,0 +1,50 @@
+/**
+ * @ai-summary Import types
+ * @ai-context Types for user data import feature (mirrors backend types)
+ */
+
+export interface ImportManifest {
+  version: string;
+  createdAt: string;
+  applicationVersion?: string;
+  userId: string;
+  contents: {
+    vehicles: { count: number; withImages: number };
+    fuelLogs: { count: number };
+    documents: { count: number; withFiles: number };
+    maintenanceRecords: { count: number };
+    maintenanceSchedules: { count: number };
+  };
+  files: {
+    vehicleImages: number;
+    documentFiles: number;
+    totalSizeBytes: number;
+  };
+  warnings: string[];
+}
+
+export interface ImportPreview {
+  manifest: ImportManifest;
+  conflicts: {
+    vehicles: number; // Count of VINs that already exist
+  };
+  sampleRecords: {
+    vehicles?: any[];
+    fuelLogs?: any[];
+    documents?: any[];
+    maintenanceRecords?: any[];
+    maintenanceSchedules?: any[];
+  };
+}
+
+export interface ImportResult {
+  success: boolean;
+  mode: 'merge' | 'replace';
+  summary: {
+    imported: number;
+    updated: number;
+    skipped: number;
+    errors: string[];
+  };
+  warnings: string[];
+}