Code-quality review found 1 Important + 2 Minor; applied all 3:
- Important: launch_rl_regime_flat_count(&mut self) → (&self)
GPU writes through device pointer are invisible to borrow checker;
matches pattern of launch_rl_win_rate_ema_update (&self) at adjacent line.
- Minor: smem_bytes → smem (matches convention of 11 other launchers)
- Minor: removed column-padding alignment on 5 new struct fields + changed
`///` doc comment to `//` for private field flat_count_d (matches surrounding
private fields).
Zero functional change.
79b8a43491