Bug: Token set folder drag-reorder scrambles order when folders are expanded

[rbosker]

Description

When dragging token set folders in the sidebar to reorder them, the order gets scrambled if the folders are expanded (children visible). Drag-and-drop reordering only works correctly when folders are collapsed first.

Steps to Reproduce

1. Open Tokens Studio for Figma plugin
2. Have multiple token set folders in the sidebar
3. Expand one or more folders so child sets are visible
4. Drag a folder to reorder it
5. Observe that the folder lands in an unexpected position and the overall order gets scrambled

Expected Behavior

Token set folders should reorder correctly regardless of whether they are expanded or collapsed.

Actual Behavior

The drag-and-drop index calculation appears to count expanded child items in the position, causing the folder to land at an unexpected index in the flat list.

Workaround

Collapse all folders before dragging them to reorder. This produces the correct result.

Environment

• Plugin version: v2.11.2 (PRO)
• OS: macOS 15.7.4

References

• Slack thread: https://tokens-studio.slack.com/archives/C02DLQXNY6Q/p1774270038468269
• Screen recording available internally (not attached here)

[rbosker]

Additional context
The scrambled order was triggered by renaming token set folders — specifically moving overrides/heading-color/* → common/heading-color/*, where the common folder already existed. After the rename, the folder order became incorrect, and drag-reorder while folders were expanded couldn't fix it properly.
Updated reproduction steps:

Have an existing token set folder structure (e.g. overrides/heading-color/)
Rename/move sets into an already-existing folder (e.g. common/heading-color/)
Observe that the folder order becomes scrambled after the rename
Attempting to fix via drag-reorder with folders expanded makes it worse
Workaround: collapse all folders, then drag to reorder

This suggests the root cause may be in how folder ordering is recalculated when sets are moved between parent folders, not just in the drag-and-drop itself.