[jxsl13]

Related to issue #835; broader codec/native coverage and evidence-based issue audit remain.

Summary

• Register PS6141 as an opt-in L3 verification advisory with no autofix. Exact typed quantizer/consumer contracts provide reviewed meaning; source analysis independently proves fresh storage, effects, normal completion and one immediate returned dot contribution.
• Support multi-call allocation/fill/consumer composition, owner-fresh destination arguments, named packed blocks and associated fixed lanes. The bounded packed-byte protocol path requires signed lane/header returned contribution and exact producer stride.
• Keep aliases, escapes, scratch/cache reuse, helper fanout, repeated traversals, multiple output rows, unsupported dynamic geometry and opaque native/table effects silent. M=1 alone is not one consumer when N rows reuse activation.
• Bind benchmark applicability exemptions to exact source/site/shape and strict observed loader target. Ordinary scans retain the original load path without extra target probes unless an enabled usable PS6141 contract needs an exemption.

Evidence and limits

Authentic retained Q8_0 encoder and scalar-half source support is separated from synthetic/MIXED complete source fixtures. Actual retained float-activation/packed-weight row kernels are negative or opaque, not invented historical activation-positive evidence. No numerical equivalence, reciprocal/approximate rewrite, portable transform or speedup is claimed.

The documented Apple M2 Pro owner observations are attributed, not locally reproduced: established median 182032 ns/op versus packed median 208481 ns/op, about 0.87x and one extra allocation. Benchmark the complete conversion/consumer boundary at the relevant target, shape, precision and lifetime.

Validation

• Scoped Go 1.26 and Go 1.27 tests; Go 1.26 race-count3, vet and matching staticcheck; independent source and integration review.
• Unchanged full pre-commit gates passed for feature commit 834bf00 and merge commit b14c572.
• Unchanged full pre-push gates passed: all 2048 race tests, matching staticcheck, current generated docs (431 checks), plugin build, required one-iteration benchmark smoke and all-level baseline self-scan.
• Integration preserves all main-only PS6136/PS6138 and CI/closure/crossover additions; diff against main is exactly 49 feature files.

Further acceptance requires exact-head CI and root review; this PR does not establish full native/model or general codec coverage.