Add model card and usage instructions

README.md

@@ -16,7 +16,7 @@ metrics:
 # LTF v3.3 — AI-generated image detection
 
 **[Try the online demo](https://huggingface.co/spaces/MuskAI/LTF-Demo)** — upload
-an original image and click Detect. The demo uses the Fusion branch at threshold
+an original image and click Analyze (开始分析). The demo uses the Fusion branch at threshold
 0.5 by default.
 
 The demo also shows exact tile boundaries, L1 per-head tile attention, L2 view