feat(indexation): integrate documents and timeline API endpoints
- Add fetchDocuments(), fetchTimeline(), deleteDocument() to Zustand store
- Connect IndexationTable to GET /indexations/documents API
- Connect WeeklyIndexingBar to GET /indexations/stats/timeline API
- Implement server-side filtering (search, source, pagination)
- Remove mock data (indexedFilesMock, weeklyIndexationMock)
- Export new types DocumentsQueryParams and TimelineQueryParams