Add status-aware now/future decoder

[lazymosemarry-png]

What changed

• add an optional status-aware now/future glimpse to the N50 and N100 decoders
• preserve the original decoder and checkpoint layout when use_now_future is disabled
• safely handle empty future sets while keeping the original final feasibility mask
• add TorchRL 0.6 dynamic-batch reset compatibility while preserving p_s_tag

Why

The experiment tests whether unserved but currently non-actionable customers
provide useful context without making infeasible actions selectable.

Validation

• Python compilation passed for all changed files
• the N50 treatment completed a 300-epoch remote training pilot with
  checkpoints every 20 epochs