Add LettuceCode mascot + tagline

README.md

@@ -21,6 +21,10 @@ datasets:
 - KRLabsOrg/lettucedetect-prose-hallucination
 ---
 
+![LettuceCode mascot](https://github.com/KRLabsOrg/LettuceDetect/blob/main/assets/lettuce_code.png?raw=true)
+
+*LettuceDetect goes agentic — span-level hallucination detection across RAG, code, and tool output.*
+
 # lettucedect-v2-mmbert-base: Encoder Hallucination Span Detection
 
 ## TL;DR — results