Add concurrency caps, the two-pane web UI, AGENTS.md, and plan status

internal/server/server.go

@@ -54,7 +54,7 @@ func New(dataDir string, spa fs.FS) (*Server, error) {
 		return nil, err
 	}
 
-	s.agents = agents.New(s.store)
+	s.agents = agents.New(s.store, agents.DefaultLimits)
 	err = s.agents.Recover(context.Background())
 	if err != nil {
 		s.store.Close()
@@ -325,6 +325,12 @@ func (s *Server) GetStatus(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	usage, err := s.agents.Usage(r.Context())
+	if err != nil {
+		writeStoreError(w, err)
+		return
+	}
+
 	dbBytes := int64(0)
 	for _, suffix := range []string{"", "-wal", "-shm"} {
 		fi, err := os.Stat(s.store.Path() + suffix)
@@ -341,9 +347,36 @@ func (s *Server) GetStatus(w http.ResponseWriter, r *http.Request) {
 		ActiveTasks:  c.ActiveTasks,
 		SseClients:   s.hub.count(),
 		LiveAgents:   s.agents.LiveCount(),
+		RunningTurns: usage.Running,
+		QueuedTurns:  usage.Queued,
+		RateLimits:   usage.RateLimits,
 	})
 }
 
+func (s *Server) ListTaskEvents(w http.ResponseWriter, r *http.Request, taskID string, params api.ListTaskEventsParams) {
+	_, err := s.store.GetTask(r.Context(), taskID)
+	if err != nil {
+		writeStoreError(w, err)
+		return
+	}
+
+	after := int64(0)
+	if params.After != nil {
+		after = *params.After
+	}
+	limit := 500
+	if params.Limit != nil {
+		limit = *params.Limit
+	}
+
+	events, err := s.store.TaskEvents(r.Context(), taskID, after, limit)
+	if err != nil {
+		writeStoreError(w, err)
+		return
+	}
+	writeJSON(w, http.StatusOK, events)
+}
+
 func (s *Server) ListSessions(w http.ResponseWriter, r *http.Request, taskID string) {
 	_, err := s.store.GetTask(r.Context(), taskID)
 	if err != nil {