refactor(display): extract dashboard tile grid logic to DisplayManager

scripts/monitor-agent.py

@@ -66,7 +66,7 @@ def cmd_reader():
                 if ready:
                     cmd = fifo.read().strip()
                     if cmd:
-                        ser.write((cmd + "\r").encode())
+                        ser.write((cmd + "\n").encode())
                         print(f"[SENT] {cmd}")
         except Exception as e:
             if cmd_running: