refactor: remove unused code and migrate legacy API

Backend cleanup:
- Remove ocr_service_original.py (legacy OCR service, replaced by ocr_service.py)
- Remove preprocessor.py (unused, functionality absorbed by layout_preprocessing_service.py)
- Remove pdf_font_manager.py (unused, never referenced by any service)

Frontend cleanup:
- Remove MarkdownPreview.tsx (unused component)
- Remove ResultsTable.tsx (unused, replaced by TaskHistoryPage)
- Remove services/api.ts (legacy API client, migrated to apiV2)
- Remove types/api.ts (legacy types, migrated to apiV2.ts)

API migration:
- Add export rules CRUD methods to apiClientV2
- Update SettingsPage.tsx to use apiClientV2
- Update Layout.tsx to use only apiClientV2 for logout

This reduces ~1,500 lines of redundant code and unifies the API client.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/Layout.tsx

@@ -1,7 +1,6 @@
 import { Outlet, NavLink, useNavigate } from 'react-router-dom'
 import { useTranslation } from 'react-i18next'
 import { useAuthStore } from '@/store/authStore'
-import { apiClient } from '@/services/api'
 import { apiClientV2 } from '@/services/apiV2'
 import {
   Upload,
@@ -29,12 +28,7 @@ export default function Layout() {
 
   const handleLogout = async () => {
     try {
-      // Use V2 API if authenticated with V2
-      if (apiClientV2.isAuthenticated()) {
-        await apiClientV2.logout()
-      } else {
-        apiClient.logout()
-      }
+      await apiClientV2.logout()
     } catch (error) {
       console.error('Logout error:', error)
     } finally {

frontend/src/components/MarkdownPreview.tsx

@@ -1,26 +0,0 @@
-import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
-
-interface MarkdownPreviewProps {
-  title?: string
-  content: string
-  className?: string
-}
-
-export default function MarkdownPreview({ title, content, className }: MarkdownPreviewProps) {
-  return (
-    <Card className={className}>
-      {title && (
-        <CardHeader>
-          <CardTitle>{title}</CardTitle>
-        </CardHeader>
-      )}
-      <CardContent>
-        <div className="prose prose-sm max-w-none dark:prose-invert">
-          <pre className="whitespace-pre-wrap break-words bg-muted p-4 rounded-md overflow-auto max-h-[600px]">
-            {content}
-          </pre>
-        </div>
-      </CardContent>
-    </Card>
-  )
-}

frontend/src/components/ResultsTable.tsx

@@ -1,90 +0,0 @@
-import { useTranslation } from 'react-i18next'
-import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from '@/components/ui/table'
-import { Badge } from '@/components/ui/badge'
-import { Button } from '@/components/ui/button'
-import type { FileResult } from '@/types/apiV2'
-
-interface ResultsTableProps {
-  files: FileResult[]
-  onViewResult?: (fileId: number) => void
-  onDownloadPDF?: (fileId: number) => void
-}
-
-export default function ResultsTable({ files, onViewResult, onDownloadPDF }: ResultsTableProps) {
-  const { t } = useTranslation()
-
-  const getStatusBadge = (status: FileResult['status']) => {
-    switch (status) {
-      case 'completed':
-        return <Badge variant="success">{t('processing.completed')}</Badge>
-      case 'processing':
-        return <Badge variant="default">{t('processing.processing')}</Badge>
-      case 'failed':
-        return <Badge variant="destructive">{t('processing.failed')}</Badge>
-      default:
-        return <Badge variant="secondary">{t('processing.pending')}</Badge>
-    }
-  }
-
-  const formatTime = (seconds?: number) => {
-    if (!seconds) return 'N/A'
-    return `${seconds.toFixed(2)}s`
-  }
-
-  return (
-    <div className="rounded-md border">
-      <Table>
-        <TableHeader>
-          <TableRow>
-            <TableHead>{t('results.filename')}</TableHead>
-            <TableHead>{t('results.status')}</TableHead>
-            <TableHead>{t('results.processingTime')}</TableHead>
-            <TableHead className="text-right">{t('results.actions')}</TableHead>
-          </TableRow>
-        </TableHeader>
-        <TableBody>
-          {files.length === 0 ? (
-            <TableRow>
-              <TableCell colSpan={4} className="text-center text-muted-foreground">
-                {t('results.noResults')}
-              </TableCell>
-            </TableRow>
-          ) : (
-            files.map((file) => (
-              <TableRow key={file.id}>
-                <TableCell className="font-medium">{file.filename}</TableCell>
-                <TableCell>{getStatusBadge(file.status)}</TableCell>
-                <TableCell>{formatTime(file.processing_time)}</TableCell>
-                <TableCell className="text-right">
-                  <div className="flex justify-end gap-2">
-                    {file.status === 'completed' && (
-                      <>
-                        <Button
-                          variant="outline"
-                          size="sm"
-                          onClick={() => onViewResult?.(file.id)}
-                        >
-                          {t('results.viewMarkdown')}
-                        </Button>
-                        <Button
-                          variant="outline"
-                          size="sm"
-                          onClick={() => onDownloadPDF?.(file.id)}
-                        >
-                          {t('results.downloadPDF')}
-                        </Button>
-                      </>
-                    )}
-                    {file.status === 'failed' && file.error && (
-                      <span className="text-sm text-destructive">{file.error}</span>
-                    )}
-                  </div>
-                </TableCell>
-              </TableRow>
-            ))
-          )}
-        </TableBody>
-      </Table>
-    </div>
-  )
-}