Add InputDeviceIconSetSO configuration guide and related documentation

- Created a new markdown file detailing the configuration of InputDeviceIconSetSO.
- Included sections on system architecture, field explanations, image specifications, and complete workflow from setup to runtime.
- Documented the automatic device recognition logic and provided troubleshooting for common issues.
- Added references to relevant files and scripts for easier navigation.

Assets/_Game/Data/UI/InputIcons/ICN_Switch.asset

@@ -0,0 +1,16 @@
+%YAML 1.1
+%TAG !u! tag:unity3d.com,2011:
+--- !u!114 &11400000
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 0}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: bf96d35cbe629854794062790e40afb7, type: 3}
+  m_Name: ICN_Switch
+  m_EditorClassIdentifier: 
+  _deviceType: 0
+  _entries: []