…w-major (was [K,N]); MODEL-1 → 100% (PMAT-CODE-SHIP-007-F32-GEMV-LAYOUT-FIX)

§74 localized the SHIP-007 PARITY-GATE bug to f32_gemv_into via PR-B's
stage-bisection scaffold (CPU vs GPU per-stage statistics analysis).
The F32 GEMV PTX kernel was reading weights with TRANSPOSED layout
interpretation:

Bug: kernel assumed A is K-rows × N-cols row-major (A[i,j] at i*N+j),
     but actual ML weights are stored [output_dim=N, input_dim=K]
     row-major (A[i,j] at i*K+j per PyTorch/SafeTensors/GGUF convention
     and PMAT-333 F32 dequantization output).

Symptom: GPU read transposed weights → computed y = A^T @ x instead
         of y = A @ x → systematically anti-correlated logits
         (cos=-0.005190 vs CPU, top-10 divergences all sign-flipped,
         CPU mean=-2.42 vs GPU mean=0.013).

Fix: rewrite the inner loop to iterate along the K dimension within
     row block_id:
       row_base = a_ptr + block_id * K * 4
       thread reads A[block_id, t], A[block_id, t+32], ...
     instead of:
       col_base = a_ptr + block_id * 4
       thread reads A[t, block_id], A[t+32, block_id], ...

Empirical discharge (canonical 7B teacher, lambda-vector RTX 4090,
default graphed path):

  PARITY-GATE: PASS (no error from forward_gpu_resident)
  Throughput @ 128-tok 5-iter decode: 124.6 tok/s
  AC-SHIP1-007 floor: 30 tok/s
  Headroom: 4.15× over floor
  TTFT: 8.39 ms
  p50 latency: 1016 ms

Before PR-E:
  PARITY-GATE FAILED cos=-0.005190
  Throughput (with SKIP_PARITY_GATE=1 + SKIP_FP8_WARMUP=1): 5.6 tok/s (§63) / 54.5 tok/s (§73)
  GPU CANNOT serve this model

After PR-E:
  PARITY-GATE PASS, default path, NO workarounds
  124.6 tok/s, 4.15× over floor

Ship-% impact:
  MODEL-1 ship %: **99% → 100%**
  10 of 10 AC-SHIP1-* LIVE-DISCHARGED:
    SHIP-001 (§72)  SHIP-002 (§61)  SHIP-003 (§72)
    SHIP-004 (§72)  SHIP-005 (§71)  SHIP-006 (§61.8)
    SHIP-007 (this PR)  SHIP-008 (§61)  SHIP-009 (§72)
    SHIP-010 (§72)

  MODEL-2 ship %: unchanged at 57% (independent track).

Cascade arc closeout: §63 → §73 → PR-A (#1648) → PR-B (#1649)
→ §74 (#1650) → PR-E (this). One PR shipped in 1 day after §73's
'3-5 PR / 3-5 day' estimate.

Auxiliary change: logits.rs adds APR_LM_HEAD_FORCE_QTYPE env-var
probe kept as a diagnostic tool (zero behavior change when unset).

Test plan:
- [x] cargo build --release -p apr-cli --bin apr --features cuda → clean
- [x] apr bench (default path, 128-tok 5-iter) → 124.6 tok/s, passed: true
- [x] apr parity → PARITY-GATE PASS
- [ ] CI tests (workspace-test on per-PR runner)

Refs:
- §74 SHIP-007 bug localized (PR #1650)
- §73 SHIP-007 cascade reduction (PR #1647)
- contracts/apr-ship-007-gpu-stage-bisection-v1.yaml (PR-A #1648 contract)
- PR #1649 (PR-B GPU stage dump scaffold)
- AC-SHIP1-007 (spec §5)
- evidence/section-75-ship-007-discharged-2026-05-13/

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>