Reworks the Genome Atlas tree into an expanding Sankey diagram.
**Sankey bars.** Each group is a bar split into annotated (green) and not-annotated (gray) assemblies. Two-tone flows carry both parts from a parent into its lineages. Bar and flow heights follow assembly counts within a column, and each column is rescaled to the full height so deep lineages stay legible.
**Expands to the right.** Clicking a group adds its lineages as a new column instead of re-rooting the view, so every ancestor stays visible. Clicking a group in an earlier column replaces the columns after it. The selection is encoded as a path (`2759/33154/33208`, with `~offset` for expanded "Other lineages"), validated server-side, so the view stays stateless. Search and the shortcuts open the full lineage of a taxon. A selected lineage outside a column's top six is pinned into that column. The view auto-scrolls to the newest column.
Other details:
- Event payload key is `route`, because Gradio treats a `path` field…
