docs: lead with the platform category, not the infrastructure

Author: chengzeyi

README.md

@@ -141,5 +141,5 @@ MIT
 
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-**[WaveSpeed AI](https://wavespeed.ai/)** — hosted inference for image, video, audio and 3D models.
+**[WaveSpeed AI](https://wavespeed.ai/)** — AI image & video generation platform.
 Try it in the browser: **[Image generator](https://wavespeed.ai/image-generator)** · **[Video generator](https://wavespeed.ai/video-generator)**