fix: allow access to agent/new on empty sessions

pathType in server.go blocked walks to agent/new when Core is nil.
Added early return for parts[2]=="new" before the nil-guard so the
agent creation file is always accessible.

Also made agent/new rdwr return the agent name instead of just "ok".

cmd/olliesrv/server.go

@@ -573,6 +573,13 @@ func (s *Server) pathType(path string) string {
 			if len(parts) == 2 {
 				return "dir"
 			}
+			// agent/new is always accessible — it creates the agent
+			if len(parts) >= 3 && parts[2] == "new" {
+				if len(parts) == 3 {
+					return "file"
+				}
+				return ""
+			}
 			// No agent in empty session.
 			if sess.Core == nil {
 				return ""

fs/session/root.go

@@ -486,7 +486,7 @@ func rootOpen(rs *rootState, name string) (File, error) {
 						if err := CreateAgent(rs, sessID, strings.Fields(strings.TrimSpace(string(data)))); err != nil {
 							return err
 						}
-						agentResult = "ok"
+						agentResult = sess.Core.Agent().Name()
 						return nil
 					},
 					BlockingReadFn: notBlocking,