Fan-sx/dsh-session-focus

Marks a Session as focus or parked in one click from its sidebar row, its hover card, or the conversation header, and keeps a count visible at the foot of the sidebar and next to workspace folder names when those groups are collapsed. A panel lists every marked Session alongside the states the sidebar already tracks (waiting for a reply, running, finished-unread), and the sidebar foot opens whichever one needs a reply first.