Load separate dqn_grad_norm_kernel instance (grad_norm_standalone)
from fresh cubin for clip_grad_buf_inplace and read_grad_norm_sync.
CUDA graph captures function handles — same CUfunction can't be
used both inside captured graph and outside on same stream.
Smoke test status: experience collection + CUDA graph capture +
forward + loss + backward all pass. Remaining blocker:
non-graph kernel launch after graph replay (needs investigation
of cudarc event tracking interaction with CUDA graphs).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>