Improve CUDA version conversion comment clarity

Co-authored-by: meizhong986 <148393222+meizhong986@users.noreply.github.com>

Author: Copilot

whisperjav/utils/preflight_check.py

@@ -150,8 +150,9 @@ def _check_pytorch_cuda(self):
                 runtime_cuda = torch.version.cuda
 
                 # Convert compiled_cuda integer to version string for comparison
-                # compiled_cuda is an integer like 12090 representing version 12.0.90
-                # runtime_cuda is a string like "12.9"
+                # compiled_cuda is an integer like 12090 representing CUDA 12.9.0
+                # We extract major.minor (12.9) to match runtime_cuda format (string "12.9")
+                # Note: Patch version is intentionally truncated as runtime_cuda doesn't include it
                 if isinstance(compiled_cuda, int):
                     major = compiled_cuda // 1000
                     minor = (compiled_cuda % 1000) // 10