feat(preflight): measure qwen35's think_format, and record why pinned cannot be

[glennneuber]

Closes the two honest skips on the gfx1151 qwen35 row. One was measurable; the other turned out not to be, and conflating those was the actual problem.

think_format — measured

On 0.32.1-dynres-5d5b7a72: 306 eval tokens, 823 chars of thinking then 517 chars of valid JSON, identical across a 2000 and a 4000 budget — so it terminates well inside the allowance, deterministically. num_predict recorded as 4000 to match this profile's other arches; it is a ceiling, not a measurement, and the headroom exists so a legitimate run never caps.

Worth recording: this arch does not hit the runaway-reasoning trap check_think_format warns about. That gate samples at temperature 0, which is off-policy for thinking and is what stops nemotron-class reasoning terminating. qwen3.8 closed its thinking block at 306 tokens under exactly that sampling.

pinned_budget — not applicable, not unmeasured

visionServerArgs builds gemma4's and nemotron_h_omni's flags from the request options, but the qwen VL family's branch returns a fixed --image-min-tokens and never reads opts. So image_min_tokens/image_max_tokens are inert for this arch.

Verified on the host rather than inferred from the source:

2048x1152 unpinned      -> 2306
2048x1152 pinned @1536  -> 2306     # byte-identical; the pin does nothing

The existing skip read "this arch's probe has not been measured. See README.md to add one" — which would send someone off to measure a value that cannot move. This adds pinned_not_applicable, a per-row reason so the skip states why. Rows without it keep the old message unchanged.

Verification

PASS  think_format [qwen35]: valid JSON after thinking (306 tokens)
skip  pinned_budget [qwen35]: pinned budget does not apply to this arch:
      image_min_tokens/image_max_tokens are arch-gated to gemma4 and
      nemotron_h_omni; qwen35's visionServerArgs branch ignores them.
PASS=18  SKIP=2        VERDICT: PASS

Up from PASS=17 SKIP=3. The one remaining skip is gemma4's pinned probe, which is genuinely unmeasured and untouched. test_verdicts.py 34 green.

🤖 Generated with Claude Code