Add Spring Festival workflows: spring_text_image, spring_text_image_EN, and spring_3d
spring_text_image – Chinese prompt version of a multi-agent content pipeline (planner → copywriter → editor → poster generation).
spring_text_image_EN – English prompt version of the same workflow structure, adapted for broader international usage.
spring_3d – A simplified 3D scene generation workflow that outputs Blender Python scripts for Spring Festival themed scenes.
