Extends the existing pointer-based session drag (session-drag.ts) with a
new resolvable target: a sidebar project row (tagged data-sessions-project
by ProjectOverviewRow). Dropping a session there calls the same
moveSessionToProject RPC the row's own "Move to project" context-menu item
already uses, so this is a faster path onto an existing capability rather
than a new one. Home and the session's current project are excluded as
targets, matching the context-menu's own filtering. The hovered project
row is highlighted imperatively (a data-drop-hover attribute + an
outline-sidebar-ring style) to keep the sidebar out of React re-render
churn during pointer travel.
c4d14871e1