Migrates the 7 in-file callers of clone_htod_f32 in DqnGpuData/PpoGpuData
constructors and helpers to mapped_pinned::clone_to_device_f32_via_pinned.
Sites: features+targets+ofi upload (DqnGpuData::upload_slices,
::upload_ofi), portfolio scratch (build_batch_states), htod_copy_into,
PpoGpuData::upload.
Helper bodies htod_f32 / clone_htod_f32 left intact at lines 129-145 —
other parallel agents are still migrating files that call them.
Audit row appended (Fix 5) in docs/dqn-gpu-hot-path-audit.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>