Added section on LED Lighting for Robotics (#184)

- covers LED use cases in robotics (illumination, communication, aesthetics)
- explains optics and implementation topics (CRI, diffusion, light piping, PWM control)
- includes practical engineering considerations (power, heat, voltage, mounting, control methods)

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Co-authored-by: Nevin Valsaraj <nevin.valsaraj32@gmail.com>

Author: Plottt

_data/navigation.yml

@@ -187,6 +187,8 @@ wiki:
         url: /wiki/actuation/task-prioritization-control/
       - title: Drive-by-wire Conversion for Autonomous Vehicle
         url: /wiki/actuation/drive-by-wire/
+      - title: LED Lighting for Robotics
+        url: /wiki/actuation/led-lights/
       - title: Selecting the Right Motor for Your Application
         url: /wiki/actuation/selecting-the-right-motor/
   - title: Machine Learning