[Bug]: Two merged identical regions cannot be edited separately — editing the pill changes both #1017

What happens

Two zooms with identical properties that touch (30.0–43.6 s and 43.6–57.1 s, same level, focus and 3D preset) render as one 2.20× pill — as intended. But selecting that pill and changing the level changed both stored regions (depth 4 → 2 on both), so the pill never separates and there is no way to edit one of the two.

Expected

Changing one of two merged regions separates the pill into two (checklist "Modifiers are anchored to clips", line 338).

Steps

1. Select a zoom, Cmd/Ctrl+C, move the playhead to its end, Cmd/Ctrl+V — one merged pill.
2. Click the pill near its end and pick another zoom level.
3. Both halves change; the pill stays merged.

Related

Repel within one clip also truncates the dragged region (zoom 27.1 s → 19.3 s; a 2× speed region 13.6 s → 1.6 s when dragged into a 1.5× neighbour) — the in-clip variant of #1008.

Environment

v2.0.0 (DMG), macOS 27.0, Mac mini M1.