The worktree dialog state was local React state in SessionSidebar,
which gets destroyed when the component unmounts (mobile drawer close,
VSCode view switch). This caused the modal to briefly appear then
disappear.
Three changes:
- Move newWorktreeDialogOpen from local state to useUIStore so it
survives component unmount
- Guard useProjectSessionSelection layout effect to skip when the
worktree dialog is open (prevents auto-session-selection from
closing the sidebar)
- Remove setSessionSwitcherOpen(false) from worktree button handler
on mobile (prevents drawer close that unmounts the sidebar)
Fixes#1414