docs(website): update TOC for SP25

Author: umanachi

src/design_notebooks/2025spring/00_toc.md

@@ -0,0 +1,19 @@
+# Spring 2025 Design Notebooks
+
+---
+
+  * [Darren Kuo](dk4461.md)
+
+  * [Rielle Lim](gil2011.md)
+
+  * [Hongtai Du](hd2609.md)
+
+  * [James Xie](hx2227.md)
+
+  * [Noah Mays-Smith](nm4207.md)
+
+  * [Uma Nachiappan](un2021.md)
+
+  * [Xingzhi Dai](xd2305.md)
+
+  * [Ben Feng](zf2179.md)