Fix/spmm name (#200)

* Document that challenge name is used for URL generation

Add note in CLAUDE.md that the `name` parameter in `__init__` is used to
generate URLs, so it should use URL-friendly characters only (no parentheses,
special symbols, etc.).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Fix name

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: kunal-mansukhani

CLAUDE.md

@@ -41,7 +41,7 @@ Must inherit from `ChallengeBase` and follow Black formatting (line length 100).
 #### `__init__`
 ```python
 super().__init__(
-    name="Challenge Display Name",
+    name="Challenge Display Name",  # Used to generate URLs — use URL-friendly characters only (no parentheses, special symbols, etc.)
     atol=1e-05,           # Absolute tolerance (float32 default)
     rtol=1e-05,           # Relative tolerance (float32 default)
     num_gpus=1,

challenges/medium/75_sparse_matrix_dense_matrix_multiplication/challenge.py

@@ -8,7 +8,7 @@
 class Challenge(ChallengeBase):
     def __init__(self):
         super().__init__(
-            name="Sparse Matrix-Dense Matrix Multiplication (SpMM)",
+            name="Sparse Matrix-Dense Matrix Multiplication",
             atol=1e-03,
             rtol=1e-03,
             num_gpus=1,