feat: documentation update

- Completed export workflow implementation (query builders, CSV/XLSX serializers, streaming API endpoints, UI modals, automated tests).
- Added export modal UI and client script to trigger downloads directly from dashboard.
- Documented import/export field mapping and usage guidelines in FR-008.
- Updated installation guide with export environment variables, dependencies, and CLI/CI usage instructions.

requirements/FR-008.md

@@ -33,6 +33,8 @@ Exporting analysis results in multiple formats is essential for users who need t
 - The export functionality should be accessible from relevant areas of the application (e.g., project dashboards, analysis results pages).
 - The system should log export activities for auditing and monitoring purposes.
 - Import and export flows must share a consistent schema contract so that data exported from the platform can be re-imported without loss.
+- Export endpoints must respect role-based access rules (analyst, project_manager, admin) and return streaming responses with proper content-disposition headers.
+- UI tooling must support triggered downloads via modal forms with format and metadata controls.
 
 ## Import/Export Field Mapping