# Change: Fix V2 API UI Integration Issues

## Why
After migrating from V1 batch-based architecture to V2 task-based architecture, several UI pages still reference V1 APIs or have incomplete implementations:
1. Results page (http://127.0.0.1:5173/results) doesn't display task details - uses non-existent V1 `getBatchStatus` API
2. Task History page markdown downloads produce empty files (0 bytes) - OCR service not generating markdown content
3. Task History page "View Details" button navigates to `/tasks/{taskId}` route that doesn't exist
4. Export page (http://127.0.0.1:5173/export) uses non-existent V1 `/api/v2/export` endpoint (404) and lacks multi-task selection
5. Admin Dashboard page loads but may have permission or API issues

These issues were discovered during testing with task ID: `88c6c2d2-37e1-48fd-a50f-406142987bdf` using file `Henkel-84-1LMISR4 (漢高).pdf`.

## What Changes
- Migrate ResultsPage from V1 batch API to V2 task API
- Fix OCR service markdown generation to produce non-empty .md files
- Add task detail page route and component at `/tasks/:taskId`
- Update ExportPage to use V2 download endpoints and support multi-task selection
- Verify and fix Admin Dashboard API integration and permissions

## Impact
- Affected specs: task-management, result-export
- Affected code:
  - Frontend: `src/pages/ResultsPage.tsx`, `src/pages/ExportPage.tsx`, `src/App.tsx` (routes), new `src/pages/TaskDetailPage.tsx`
  - Backend: `app/services/ocr_service.py` (markdown generation), `app/routers/tasks.py` (download endpoints)