Renders the Compare page — three states keyed off the session
library + URL ?ids=:
No sessions imported — <NoSessionsEmpty> takes over with
a single primary Import action.
Fewer than two selected — <PickStage> renders the
searchable picker (max 4) with an explainer sidecar.
Two or more selected — the overlay view (<OverlayView>)
renders the stacked overlay charts + summary table.
Each state is a separate function component so hook order stays
consistent within each branch — the overlay view memoizes the
dataset, the picker manages local set state, and the empty state
carries no hooks at all.
Renders the Compare page — three states keyed off the session library + URL
?ids=:<NoSessionsEmpty>takes over with a single primary Import action.<PickStage>renders the searchable picker (max 4) with an explainer sidecar.<OverlayView>) renders the stacked overlay charts + summary table.Each state is a separate function component so hook order stays consistent within each branch — the overlay view memoizes the dataset, the picker manages local set state, and the empty state carries no hooks at all.