🌅 docs: Add OpenAI Image Gen Env Vars (danny-avila#10335)

Author: Educg550

.env.example

@@ -254,6 +254,10 @@ AZURE_AI_SEARCH_SEARCH_OPTION_SELECT=
 
 # OpenAI Image Tools Customization
 #----------------
+# IMAGE_GEN_OAI_API_KEY= # Create or reuse OpenAI API key for image generation tool
+# IMAGE_GEN_OAI_BASEURL= # Custom OpenAI base URL for image generation tool
+# IMAGE_GEN_OAI_AZURE_API_VERSION= # Custom Azure OpenAI deployments
+# IMAGE_GEN_OAI_DESCRIPTION=
 # IMAGE_GEN_OAI_DESCRIPTION_WITH_FILES=Custom description for image generation tool when files are present
 # IMAGE_GEN_OAI_DESCRIPTION_NO_FILES=Custom description for image generation tool when no files are present
 # IMAGE_EDIT_OAI_DESCRIPTION=Custom description for image editing tool