fs/session: restore normal blocking semantics for statewait

statewait is a blocking wait file with a 5-second timeout, not an
indefinite long-block stream like chat. Remove LongBlock=true so the
9P server uses the normal blocking path (WithTimeout 5s) instead of
WithCancel-only behavior.

Also remove temporary statewait debug instrumentation.

cmd/olliesrv/server.go

@@ -876,6 +876,10 @@ func (s *Server) read(cs *connState, fc *plan9.Fcall, ctx context.Context) *plan
 		return errFcall(fc, err.Error())
 	}
 
+	if strings.HasSuffix(path, "/statewait") {
+		s.log.Debug("statewait read path=%q isBlocking=%v longBlock=%v oneShot=%v", path, entry.IsBlocking(), entry.LongBlock(), entry.OneShot())
+	}
+
 	// OneShot entries yield data once per open; offset>0 means EOF.
 	if entry.OneShot() && fc.Offset > 0 {
 		return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Count: 0}

fs/session/files.go

@@ -367,14 +367,11 @@ func (h *agentHelper) fileSpec(name string, mode os.FileMode) FileSpec {
 			if base == "" {
 				base = h.ag.State()
 			}
-			h.log.Debug("statewait: begin base=%q ag=%q", base, h.ag.Name())
 			v, ok := h.ag.WaitChange(ctx, agent.WatchState, base)
 			if !ok {
 				s := h.ag.State()
-				h.log.Debug("statewait: !ok returning state=%q", s)
 				return []byte(s + "\n"), s, nil
 			}
-			h.log.Debug("statewait: ok returning state=%q", v)
 			return []byte(v + "\n"), v, nil
 		}
 	}