Added trigger

docs/OSC_CONTROL.md

@@ -70,6 +70,12 @@ Examples:
 
 Values are validated with the same shader parameter rules used by the REST API. Invalid values or unknown addresses are ignored and reported to the native debug output.
 
+For `trigger` parameters, the OSC value is treated as a pulse. A simple integer or boolean message is enough:
+
+```text
+/VideoShaderToys/trigger-flash/flash 1
+```
+
 ## Open Stage Control
 
 For simple scalar controls, set the widget address and target directly: