Epic: Grid Unified Scrolling & VDOM Orchestration

This epic tracks the architectural pivot of the Grid Multi-Body structure to a unified vertical scrolling mechanism and centralized VDOM orchestration.

The Problem

Currently, the Grid V2 splits the grid into three independent scrolling bodies (bodyStart, body, bodyEnd) that sync their offsets dynamically. However, since they update their VDOM payloads independently via their own calculation loops, the larger center body (with more unlocked columns) requires more time to calculate delta patches than the start/end bodies. This results in staggered, non-deterministic VDOM updates arriving on the main thread, leading to horizontal tearing and jitter during rapid scrolling.

The Solution: grid.View

We are flattening the child grid.Body components to be strictly full-height data strips (no internal scrolling, no stretchers). We introduce a new overarching orchestrator class, neo.grid.View (acting as the unified bodyWrapper), which manages vertical scrolling natively.

This grid.View class will take over the createViewData calculation cycle. During a scroll event, the View calculates the new row index limits and instructs all internal bodies to update their view data silently (silent: true). Once all sub-grids are prepared, the View triggers a single, unified VDOM update (this.update({updateDepth: -1})), guaranteeing that the entire scroll state is painted atomically by the compositor thread.