Fix Fleet AI and LOTL test regressions after parallel merges.

Stub slow syscheck/listen-port probes in agent tests, fix ai_snapshot mutex deadlock, reorder fleet clearance vs connectivity checks, and add AI control precedence plus LotlTimeline vitest coverage.

server/internal/api/websocket_test.go

@@ -52,6 +52,22 @@ func dialAgentWS(t *testing.T, hub *WSHub) (*websocket.Conn, string) {
 	return conn, wsURL
 }
 
+func readAgentWSMessage(t *testing.T, conn *websocket.Conn, wantType string) Message {
+	t.Helper()
+	deadline := time.Now().Add(5 * time.Second)
+	for time.Now().Before(deadline) {
+		var msg Message
+		if err := conn.ReadJSON(&msg); err != nil {
+			t.Fatalf("read %s: %v", wantType, err)
+		}
+		if msg.Type == wantType {
+			return msg
+		}
+	}
+	t.Fatalf("timed out waiting for %s", wantType)
+	return Message{}
+}
+
 func authAgentConn(t *testing.T, conn *websocket.Conn, payload map[string]interface{}) Message {
 	t.Helper()
 	data, _ := json.Marshal(payload)