# UnifiedSpread dev-24.0.0 Worksheet Completion Foundation

This milestone consolidates the confirmed remaining feature groups through the dev-24 roadmap while keeping UnifiedSpread as a Host-embeddable AMD package.

## Implemented areas

- UI interaction stability: grid, popup, context menu and object commands continue to route through CommandRegistry / CommandRouter.
- Chart/Object foundation: chart options command, refresh/switch, z-order, lock, nudge and inline text editing remain preserved.
- XLSX round-trip foundation: UnifiedSpread-native metadata is written to a hidden `__UnifiedSpreadMetadata` sheet so comments, protected ranges, pivots and objects can survive export/import even before full OOXML drawing/comment writers are implemented.
- Formula recalculation scheduler metadata: workbook config tracks dirty formula regions, last recalculation time and formula error metadata.
- Pivot foundation: selected table ranges can create a new Pivot sheet using first-row headers, first-column row labels and SUM aggregation for numeric columns.
- Collaboration metadata: cell comments, workbook change log and protected ranges are persisted in workbook config and in `.uspdx`.
- Large-data rendering seam: the NativeGrid renderer continues to use bounded rendering and now documents the virtual rendering expansion point explicitly.

## Design notes

The implementation favors stable internal contracts over a heavy UI panel in this milestone.  Every user-visible operation is exposed as a command, so Host systems can replace the simple demo/default behavior with richer dialogs without changing the model or file format.