feat: GF-T on-chip trainer primitive (forward+grad+update, proven on AX7203)

[gHashTag]

Single-commit replacement for #1816 (that branch had docs commits without issue refs → L1 traceability). New spec gft_train1.t27 — on-device training primitive: on_comb(w,x,t,eta) runs one full SGD step (forward y=wx, error e=y-t, gradient g=ex, update w-etag) combinationally, reusing gft_sgd_step helpers. In-spec 3/3, iverilog bit-exact. Proven on a live AX7203 (uart_train1.v): with the weight in a register the whole forward+backward+update runs on-chip; streaming (x, t=1.5x) the board converges 0.25->~1.42 toward hidden w*=1.5. docs/NOW.md updated. Refs #1764

[github-actions]

📓 NotebookLM Notebook linked to this PR

• Notebook ID: b83263109fb055dc
• URL: https://notebooklm.google.com/notebook/b83263109fb055dc

This notebook contains session context, decisions, and artifacts for this work.

[github-actions]

PR Dashboard

Generated at: 2026-08-07 00:05:19 UTC

• feat: GF-T on-chip trainer primitive (forward+grad+update, proven on AX7203) #1817 feat: GF-T on-chip trainer primitive (forward+grad+update, proven on AX7203) | Created: 2026-08-07 | Updated: 2026-08-07 | 10 failing / 15 total
• feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1815 feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 1 total
• feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1813 feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 12 total
• feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1810 feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 12 total

Summary

Status	Count
Total Open PRs	4
PRs with Failing Checks	0
PRs with All Checks Green	4
READY	3
FAILING	0
PENDING	0

Seal Status

• ⚠️ STALE -- sha256(compiler.rs)=4c1aaad5309a != manifest seal=87e5cbd3ad94.
  The committed NMSE numbers were certified against an older compiler.rs.
  Run scripts/reseal-check.sh locally for the two-step reseal command (advisory; not a merge gate).