Update README with LeetCode Daily Challenge

Author: jeremymanning

README.md

@@ -28,6 +28,7 @@ This means you'll always find an AI-generated solution to compare with or learn
 | January 6, 2026 | [1161](https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1161) | 🟡 Medium |
 | January 7, 2026 | [1339](https://leetcode.com/problems/maximum-product-of-splitted-binary-tree/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1339) | 🟡 Medium |
 | January 8, 2026 | [1458](https://leetcode.com/problems/max-dot-product-of-two-subsequences/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1458) | 🔴 Hard |
+| January 9, 2026 | [865](https://leetcode.com/problems/smallest-subtree-with-all-the-deepest-nodes/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/865) | 🟡 Medium |
 
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