feat(monitor): agent.started + agent.complete channel notifications

- emitStartEvent fires when agent spawns (dispatch.go)
- Monitor detects new "running" workspaces and pushes agent.started
  channel notification with repo and agent info
- agent.complete already included blocked/failed status — no change
- Both old and new workspace layouts supported

Co-Authored-By: Virgil <virgil@lethean.io>

pkg/agentic/dispatch.go

@@ -145,6 +145,9 @@ func (s *PrepSubsystem) spawnAgent(agent, prompt, wsDir string) (int, string, er
 	proc.CloseStdin()
 	pid := proc.Info().PID
 
+	// Emit start event for channel notifications
+	emitStartEvent(agent, core.PathBase(wsDir))
+
 	go func() {
 		ticker := time.NewTicker(5 * time.Second)
 		defer ticker.Stop()

pkg/agentic/events.go

@@ -22,14 +22,12 @@ type CompletionEvent struct {
 	Timestamp string `json:"timestamp"`
 }
 
-// emitCompletionEvent appends a completion event to the events log.
-// The plugin's hook watches this file to notify the orchestrating agent.
-// Status should be the actual terminal state: completed, failed, or blocked.
-func emitCompletionEvent(agent, workspace, status string) {
+// emitEvent appends an event to the events log.
+func emitEvent(eventType, agent, workspace, status string) {
 	eventsFile := core.JoinPath(WorkspaceRoot(), "events.jsonl")
 
 	event := CompletionEvent{
-		Type:      "agent_completed",
+		Type:      eventType,
 		Agent:     agent,
 		Workspace: workspace,
 		Status:    status,
@@ -50,3 +48,13 @@ func emitCompletionEvent(agent, workspace, status string) {
 	defer wc.Close()
 	wc.Write(append(data, '\n'))
 }
+
+// emitStartEvent logs that an agent has been spawned.
+func emitStartEvent(agent, workspace string) {
+	emitEvent("agent_started", agent, workspace, "running")
+}
+
+// emitCompletionEvent logs that an agent has finished.
+func emitCompletionEvent(agent, workspace, status string) {
+	emitEvent("agent_completed", agent, workspace, status)
+}

pkg/monitor/monitor.go

@@ -78,6 +78,7 @@ type Subsystem struct {
 	// Track last seen state to only notify on changes
 	lastCompletedCount int             // completed workspaces seen on the last scan
 	seenCompleted      map[string]bool // workspace names we've already notified about
+	seenRunning        map[string]bool // workspace names we've already sent start notification for
 	completionsSeeded  bool            // true after first completions check
 	lastInboxMaxID     int             // highest message ID seen
 	inboxSeeded        bool            // true after first inbox check
@@ -124,6 +125,7 @@ func New(opts ...Options) *Subsystem {
 		interval:      interval,
 		poke:          make(chan struct{}, 1),
 		seenCompleted: make(map[string]bool),
+		seenRunning:   make(map[string]bool),
 	}
 }
 
@@ -304,6 +306,15 @@ func (m *Subsystem) checkCompletions() string {
 			}
 		case "running":
 			running++
+			if !m.seenRunning[wsName] && seeded {
+				m.seenRunning[wsName] = true
+				if m.notifier != nil {
+					m.notifier.ChannelSend(context.Background(), "agent.started", map[string]any{
+						"repo":  st.Repo,
+						"agent": st.Agent,
+					})
+				}
+			}
 		case "queued":
 			queued++
 		case "blocked", "failed":