feat: terminal tabs - several machines at once, up to four terminals split in a tab by drag and drop, resizable, renamable; the top bar keeps its status in sight

internal/server/handlers_panel.go

@@ -151,14 +151,17 @@ func (s *Server) handlePresence(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	type item struct {
-		ID     string `json:"id"`
-		Online bool   `json:"online"`
-		Seen   string `json:"seen"`
+		ID       string `json:"id"`
+		Name     string `json:"name"`
+		Hostname string `json:"hostname"`
+		User     string `json:"user"` // who a terminal opens as
+		Online   bool   `json:"online"`
+		Seen     string `json:"seen"`
 	}
 	out := make([]item, 0, len(agents))
 	for _, a := range agents {
 		on := s.online(&a)
-		out = append(out, item{ID: a.ID, Online: on, Seen: seenText(on, a.LastSeen)})
+		out = append(out, item{ID: a.ID, Name: a.Name, Hostname: a.Hostname, User: a.TerminalUser(), Online: on, Seen: seenText(on, a.LastSeen)})
 	}
 	writeJSON(w, out)
 }