[pyrex41]

Vendors upstream Shen-Language/shen-sources ec16a9f. That is the 43.1 release plus shen-sources#117: shen.by-hypothesis and shen.search-user-datatypes dereference the checked term once per call through new -h predicates, and fail at once on an empty list. The PR then makes the native typechecker follow that kernel without falling back. (version) is still "43.1".

Commits

1. kernel: the 23 klambda/*.kl files, byte-identical to ShenOSKernel-43.1-ec16a9f.tar.gz (https://github.com/pyrex41/shen-sources/releases/tag/upstream-ec16a9f, sha256 060066a8f84d9a2f7d41cb3b37b986a8d4653279752b739b5063cd648d9baacd). The commit also updates klambda/PROVENANCE.md, klambda/README.md and the CHANGELOG. tests/ is unchanged and identical to the archive.
2. typecheck: follow the ec16a9f kernel natively. On the vendored kernel alone, the conformance spec fails 5 checks, and the native path falls back to the KL typechecker for two reasons:
   • Fingerprint: shen.search-user-datatypes has a new fingerprint (483d69ab4d98d601). typecheck_native.lua now accepts it. The only change from the deref-hoist shape it already accepted is the empty-list guard. The hand port already fails on an empty list before any clause, counts no inference there (the -h clauses never match []), and never copies on deref. shen.search-user-datatypes-h has the same fingerprint as the hoist shape.
   • Translator: the translated shen.by-hypothesis now starts with (if (= (shen.lazyderef Hyp B) ()) false ...). The translator refused it ("goal call with <4 args: shen.lazyderef"). prolog_compile.lua now treats a (shen.lazyderef X B) of a term variable as an engine term in =, so the guard compiles to an arena comparison: LZD(x) == NIL. Plain shen.deref is deliberately not accepted there, because it is the identity in term position.
   • Spec: kernel_conformance_spec now expects the vendored kernel's hoisted shape. The driver closure adds shen.by-hypothesis-h, and eqterm still fires in shen.by-hypothesis-h.

Gates (local, LuaJIT 2.1.1785763465)

• make test: 1797 pass, 0 fail across 29 specs. kernel_conformance_spec is 23/0.
• make certify: 154 / 0, with inference counts identical to main. Also 154 / 0 under SHEN_TYPECHECK_NATIVE=require.
• capcov shenbench, 8 workloads: 8/8 payloads byte-identical to the go-1f587de reference. The run also passes 8/8 under SHEN_TYPECHECK_NATIVE=require. No stderr contains a fallback notice.

Speed (b-typed, /usr/bin/time -l, one pair)

	CPU	instructions
main c6c3a22	12.0 s	140.6 G
this branch	11.2 s	142.8 G (+1.6%, noise)

As expected, this is flat. shen-lua's native engine never copies on deref, and #96 eqterm already removed the by-hypothesis materialisation. The kernel change matters here only for staying native on the upstream kernel.

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