Update README with LeetCode Daily Challenge

Author: jeremymanning

README.md

@@ -40,6 +40,7 @@ This means you'll always find an AI-generated solution to compare with or learn
 | November 18, 2025 | [717](https://leetcode.com/problems/1-bit-and-2-bit-characters/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/717) | 🟢 Easy |
 | November 19, 2025 | [2154](https://leetcode.com/problems/keep-multiplying-found-values-by-two/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/2154) | 🟢 Easy |
 | November 20, 2025 | [757](https://leetcode.com/problems/set-intersection-size-at-least-two/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/757) | 🔴 Hard |
+| November 21, 2025 | [1930](https://leetcode.com/problems/unique-length-3-palindromic-subsequences/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1930) | 🟡 Medium |
 
 </details>