feat(core): pure loadUwrProfile validator (PR-UWR-RUNTIME-LOADER)

[Gio2050]

Slot and authorization

This PR executes PR-UWR-RUNTIME-LOADER — the afi-core row of the §7 authorization ledger in afi-governance decisions/uwr-runtime-consumption-v0.1.md.

Go-ahead (RC-10.5): the row was flipped to "Yes — row flip merged by owner per RC-12 (recorded 2026-07-13)" by owner merge of afi-governance PR #11 (merge commit fbd0c46).

What this adds

validators/UwrProfileLoader.ts — a pure loadUwrProfile(profileJson: unknown): Readonly<UniversalWeightingRuleConfig> validator/mapper. No fs, no path resolution, no afi-config dependency: the caller supplies the already-parsed document. It enforces the RC-5 identity predicate exactly:

1. four weights strictly equal defaultUwrConfig's per axis (near-misses refused, incl. 1-ULP drift);
2. axes array equals ["structure", "execution", "risk", "insight"] in content and order (UP-4);
3. profileId equals the pinned uwr-weighted-lifts-v0.1 and supersedes equals defaultUwrConfig.id (uwr-default-stub);
4. ids are never compared for direct equality — supersession, not equality, is the pinned relation.

Refusals throw UwrProfileLoadError with a machine-checkable reason (the RC-4 fail-closed triggers for the future PR-UWR-RUNTIME-READ). Fail-closed hardening: all document fields are read once, as own properties only (inherited/prototype-supplied values and accessor-backed documents cannot satisfy the predicate or alter values post-validation), and the returned frozen config spreads defaultUwrConfig itself with the registered profile id — identity by construction: registry-supplied numbers can never flow into the result. The returned id records which governed profile the values were validated against; it does not signal registry consumption (RC-6/RC-8 semantics unchanged).

validators/__tests__/UwrProfileLoader.test.ts — 20 vitest tests: happy path, frozen/no-mutation, RC-5 identity with defaultUwrConfig, bit-identical computeUwrScore under loaded vs default config (incl. the UP-5 golden anchor 0.1875), full refusal matrix (shape, schema, profileId incl. alias-as-id and stub-id, supersedes, axes reorder/drop/extend/rename, weights shape/near-miss/NaN), hostile-input hardening (single-read accessors, prototype-chain inputs), and a dev-only sibling-registry integration test (it.skipIf, same pattern as the KAT suites) proving the live afi-config registry document loads.

validators/UniversalWeightingRule.ts — the RC-8-sanctioned TODO comment update only (+5/-1 comment lines; defaultUwrConfig values and computeUwrScore signature byte-untouched).

No subpath-export change was required: the existing "./validators/*" wildcard already exposes afi-core/validators/UwrProfileLoader.js (emission to dist/validators/ verified).

Validation (RC-10 gates)

• afi-core vitest: 216 passed (216) — 196 baseline (both KAT executor suites included) + 20 new; build and typecheck green.
• afi-config pin guards: CI-enforced on its main (ce8c1de), untouched by this PR.
• afi-reactor: no changes (goldens trivially byte-stable); jest allowlist not applicable — the new tests are afi-core vitest, autodiscovered (CI runs npm test --if-present → vitest, which auto-selects non-watch run mode under CI; the build check passed on this head).
• Adversarial scope check: diff touches exactly the three files above; no KAT vectors, schemas, registry files, or sibling repos.

Review

An 8-angle adversarial review ran before opening. Fixed: single-read/own-property hardening (TOCTOU + prototype-chain false-accepts), identity-by-construction return, WEIGHT_KEYS derived from the pinned axes and compile-checked against UniversalWeightingRuleConfig, merged validation loops (casts eliminated), test dedup. Declined with rationale: zod rewrite (predicate deliberately reads literally as RC-5 for auditability; reason codes are the contract), fixture trimming (the inline mirror is CI's only realistic-document coverage since the sibling test skips there), and two findings whose fixes exceed this slot's authorization — noted below.

Notes for the owner (out of this slot's scope, no action taken)

• Provenance note: the RC-8 TODO edit is the first change to validators/UniversalWeightingRule.ts since 390b440, so the blob-identity wording in validators/__tests__/kats/README.md and the KAT test header ("blob-identical between 390b440 and 2541853") stays true as a claim about those pinned commits but no longer extends to HEAD. Comment-only divergence; the executable sha256 pin covers the KAT JSON and is untouched. Suggest folding a two-line dated addendum into PR-UWR-KAT-RERUN.
• Cross-repo pin duplication: afi-reactor's UWR_PROFILE_ID and this loader's PINNED_UWR_PROFILE_ID both hardcode the profile id with no test asserting their equality (the reactor guardrail cross-checks against the sibling registry, which transitively ties them). A reactor-side import or guardrail extension belongs to PR-UWR-RUNTIME-READ / STAMP-SEMANTICS.

Scope guarantees

No runtime registry read; no reactor changes; no scoring behavior change (loaded config is provably value-identical — golden anchor asserted); no reward/mint/settlement; defaultUwrConfig unmodified; no KAT/schema/registry values touched; UP-8 untouched; testnet-provisional throughout; no production scoring-law claim.

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