Break down the monolithic Gallery and Timeline components into smaller, highly cohesive modules to improve maintainability and separation of concerns.
- Extract core UI elements into dedicated components (`ImageTile`, `TruncatedFilename`, `ScrubberYearBlock`).
- Separate loading and empty states into dedicated files (`GalleryEmptyState`, `TimelineEmptyState`).
- Move complex timeline grouping, row virtualization mapping, and duration formatting logic into utility files (`timelineModel.ts` and `format.ts`).
- Abstract shared data structures into `types.ts` to cleanly decouple domain logic from the presentation layer.
LyAhn