Expands the NaN flag buffer from 24 to 48 slots to make room for
backward-path NaN checks (slots 24-35 per audit doc per-slot table)
plus 12 reserved headroom slots (36-47) for SP2 framework + SP3
observer hooks.
Touches:
- gpu_dqn_trainer.rs: alloc size 24→48 (line ~11178); read_nan_flags
signature [i32; 24]→[i32; 48] (line ~14982); field docstring updated
(line ~2658) to reflect 48-slot layout
- fused_training.rs: pub(crate) read_nan_flags signature [i32; 24]→[i32; 48]
- training_loop.rs: BOTH name table sites (halt_nan + halt_grad_collapse
block from commit d1808df14) updated to 48 entries
Slot names use audit allocation (docs/dqn-backward-nan-audit.md per-slot
table), which supersedes the plan's placeholder names per the audit's
plan-supersession note. Slots 24-35 cover production buffers:
d_value_logits_buf, d_adv_logits_buf, iqn_trunk_m, iqn_d_h_s2_ptr,
d_branch_logits_buf, cql_d_value_logits, aux_dh_s2_nb_buf,
ensemble_d_logits_buf, bn_d_concat_buf, bw_d_h_s2 (×3 call sites).
Slots 36-47 are rsv36-rsv47 (headroom).
No behavioral change — new slots stay at zero until Task 4 wires the
kernel-output NaN checks. Buffer size reviewable by SP2.
53bc0bc505