feat(#810 A3): NemotronH gets its ABI driver, and the reason its gate has not run gets corrected

[localai-bot]

The A2-P spec's ## Owed lists two things this row carries and one it cannot:
the thin ABI driver, the docs/USAGE.md weights block that rides with it, and
the A3 end-to-end token gate. The first two land here. The third did not run,
and the reason on record for why it has not run turned out to be wrong.

Issue: #810.

examples/nemotron_h_gen

Modelled on examples/kimi_linear_gen exactly as the governing spec §6.1
requires: one project include (vllm.h), linked against vllm::shared, and no
scripts/example-abi-allowlist.txt row, because it reaches no internal header.
check-surface-coverage.py counts 18 example units with the same 8 reaching
internal headers as before. deepseek_v4_gen and laguna_gen were deliberately
not copied; both drive a bespoke forward through internal headers and are the
transition state that allowlist exists to retire.

The golden is JSON rather than the .npy plus raw-i32 pair Kimi's battery uses,
so the driver carries a small scanner for that one committed shape. It refuses a
shape it does not recognise instead of returning an empty vector, because an
empty vector downstream is a comparison over zero elements and a comparison over
zero elements reports a perfect score.

The guards are proven armed against a real engine, not argued for. The
driver is model-agnostic, so it was exercised on a small local checkpoint:

arm	result
golden width 8, all 8 match	STRICT PASS, exit 0
golden width 8, 0 of 8 match	DIVERGENCE, exit 1
--steps 4 against golden width 8, 4 of 4 matched	SHORT, exit 4
5 malformed goldens	parse refusal, exit 2 each

The third row is the one that matters. It matched every token it looked at and
still refused, because it had looked at half the golden.

The A3 gate has not run, and its cause was wrong TWICE

First cause, dead: contention. The A2-P spec records dgx.casa at loadavg 211
with 3 of 119 GB. Re-measured under a lease, the box is idle at loadavg 0.36 with
115 of 119 GB free and the GPU at 0%, checkpoint present and revision-verified.

Second cause, also dead, and it was mine: this branch briefly claimed no CUDA
binary could be built at all. That was a HOST measurement reported as a
CONTAINER measurement, and for this purpose they are different machines.
Measured inside rc run, the worker container is Ubuntu 24.04 running as uid 0
with gcc, g++, cmake, ninja, make, python3, git and apt present,
the GB10 visible to nvidia-smi, and working DNS. Only nvcc is absent, and
apt's nvidia-cuda-toolkit 12.0.140 is too old for sm_121a, so CUDA 13.x
installs from the NVIDIA repo. Neither docker nor sudo is involved, and the
earlier ask for them is withdrawn. The host toolchain finding
(#1019) is real but gates
nothing, because the host is not where work runs.

The checkpoint sentences were wrong the same way, and are corrected against
findmnt rather than paraphrase:

/usr/local/nas_share //192.168.68.102/Data cifs rw,relatime,vers=3.1.1,...

The checkpoint resolves under BOTH /usr/local/nas_share/checkpoints/... and
~/ckpt/..., so .env's CHECKPOINT_ROOT is correct and was not "fixed".

Corrected in place, with the wrong claim kept beside the correction. A
known-false line left inside a landed record is worse than the original error,
because the next reader cannot tell it apart from the parts that were right, and
the two-machine confusion is the part worth keeping.

Genuinely outstanding: install nvcc in the build container, and whether that
container can see $CHECKPOINT_ROOT, which is OPEN and claimed by nobody.
docs/BENCHMARKS.md records the gate as pending a named resource, never as a
pass. Arm 2 of the gate (three prompts concurrent and interleaved) stays blocked
by design: G-SAFE refuses num_reqs > 1 and A2-B owns that clause.

scripts/runner-routing-allowlist.txt:26 STAYS, decided by mutation

nemotron_h.cpp:1031-1034 still refuses the NVFP4 lm_head on a non-CPU queue,
so the forward returns HostLogits. Deleting the entry in a scratch copy takes
check-runner-routing-consistency.py from OK to ERROR naming
ForwardNemotronHForCausalLM returns HostLogits, exit 1; the tree was restored
byte-for-byte. A2-Q2b removes it. The allowlist was not widened.

Records

docs/USAGE.md gains the weights block AGENTS.md requires in the change that
makes the capability reachable: repo, revision, staged path, byte total, the
verified sha256 of the first shard, and every arm named, including the four
refused ones. Its stale "refuses to run" row is corrected, and it says plainly
that no token gate result exists yet. No lifecycle state changed, so no
docs/STATUS.md write is owed.

FOLLOWING_AGENTS_PROTOCOL

Following-Agents-Protocol: true
AI-Assisted: true
Assisted-by: AGENT:claude-opus-5 [claude-code]