_t4b_closed_loop_authored.nx

_t4b_closed_loop_authored.nx -- T4b: the CLOSED-LOOP FIRST TURN. The first model trained EXCLUSIVELY on team-generated, gate-verified data: the synthesis corpus (knowledge/library/synth_corpus.log SYNTH rows). Task: expr -> spec (which spec does this team-synthesized expression solve), an exact 7-class mapping (verified conflict-free). Uses the NEW verified-gradient CE loss (tg_celoss op 6, gradcheck-gated) -- the one-hot-MSE workaround is retired on its first outing. The T4 lesson set is APPLIED, not rediscovered: centered features, inverse-frequency class weights, full-batch accumulation + gated AdamW, deterministic early stop. Emits a machine-readable training report (knowledge/status/train_report_t4b.log TRIAGE-* rows) for the nx_train_triage organ. GATES: P parse+dict+consistency (identical features MUST agree on the label -- the under-determined-data check) | Q trained to 100% (per-class pred counts == data counts, loss decreased) | R BIT-EXACT two-run. Tamper hook: argv[1] corpus path override. LAWS: struct-free, flat ifs, no &&/||, no unary-minus literals. license_tier: ORIGINAL