test(web): restore main's right-panel migration expectations after the panel-visibility merge

The keep-both merge nested main's plan-surface migration test inside a
branch popover test and dropped the threadPanelVisibilityByThreadKey key
from the migration results. Restore main's test body and include the
branch's (empty) visibility map in the expected persisted shape.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
0c0b04ea94Julius Marminge committed on 9/18/2026, 12:49:49 AM· committed by Julius Marmingeparent3480bfe
1 file changedLine totals unavailable