test: cross-product Instant Preview's evidence-key pair with the adapter's

`evidence-key-agreement.test.ts` cross-products 144 adversarial combinations
across the mock adapter's gate and descriptor resolver, `validateWorkingCopy`
and the shared pixel resolver -- but omitted `instant-preview.tsx`'s own gate
and descriptor resolver. That pair is byte-parallel to the adapter's (it
lives in `presentation/`, which may not import `adapters/`, so it carries its
own copy of the legacy-key predicate) and it is exactly the pair three earlier
fix rounds regressed.

`instant-preview.tsx` now exports the two expressions it already used, so the
test drives the production code rather than rebuilding it. Added assertions:
gate agreement in both array orders, descriptor equality with the adapter's,
pixel/descriptor agreement, and order independence. The one sanctioned
divergence -- the legacy static key's `assetId`, a fixed literal here versus a
registry-derived one there -- is pinned to that case rather than ignored.

Mutation-checked: breaking the legacy predicate reports 96 of 144 combinations
disagreeing, breaking the legacy descriptor path reports 64 of 144.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/features/tech-log/evidence-key-agreement.test.ts

@@ -9,6 +9,16 @@
 // agreement itself, through production entry points only.
 //
 // Against fix round 3's code this reported 53 of 144 combinations disagreeing.
+//
+// The callers covered are the mock adapter's projection gate and descriptor
+// resolver, `validateWorkingCopy`, the shared pixel resolver, and -- added in
+// the final fix wave -- `instant-preview.tsx`'s own gate and descriptor
+// resolver. The last pair is byte-parallel to the adapter's (they live in
+// different layers: `presentation/` may not import `adapters/`), and is the
+// pair three earlier fix rounds regressed. Its one sanctioned divergence is
+// the legacy static key's `assetId`, which the assertions below pin rather
+// than ignore. Mutating either half of that pair reports 96 and 64 of 144
+// combinations disagreeing respectively.
 
 import assert from "node:assert/strict";
 import { test } from "vitest";
@@ -18,6 +28,10 @@ import { projectWorkingCopy } from "../../../src/features/tech-log/adapters/mock
 import { validateWorkingCopy } from "../../../src/features/tech-log/adapters/mock/validate-working-copy.ts";
 import { isSupportedEvidenceKey } from "../../../src/features/tech-log/adapters/static/evidence-assets.ts";
 import { createAssetCatalogResolver } from "../../../src/features/tech-log/presentation/shared/public-render/asset-resolvers.ts";
+import {
+  instantPreviewEvidenceKeyGate,
+  resolveInstantPreviewAssetDescriptor,
+} from "../../../src/features/tech-log/presentation/studio/components/instant-preview.tsx";
 import { ContentFormatError } from "../../../src/features/tech-log/domain/content-format/parse-case-content.ts";
 
 const LEGACY = "fetch-strategy-boundary";
@@ -185,6 +199,17 @@ test("gate, projection resolver, pixel resolver and validation never disagree",
       // 1. Validation and the preview projection accept exactly the same keys.
       check(!unsupported === projected.accepted, `${where}: validation and projection disagree`);
 
+      // 1b. Instant Preview's gate is a fourth caller of the same decision,
+      //     living in `presentation/` (which may not import `adapters/`) and
+      //     therefore carrying its own copy of the legacy-key predicate. It
+      //     must accept exactly the same keys, in either array order.
+      const previewAccepts = instantPreviewEvidenceKeyGate(assets)(key);
+      check(previewAccepts === projected.accepted, `${where}: Instant Preview gate and the projection disagree`);
+      check(
+        instantPreviewEvidenceKeyGate([...assets].reverse())(key) === previewAccepts,
+        `${where}: order-dependent Instant Preview gate`,
+      );
+
       if (!projected.accepted) {
         check(projected.error instanceof ContentFormatError, `${where}: expected a gate rejection, got ${String(projected.error)}`);
         check(
@@ -227,6 +252,46 @@ test("gate, projection resolver, pixel resolver and validation never disagree",
       const emptyAlt = validate(key, "", assets);
       const altRequired = emptyAlt.issues.some((issue) => issue.code === "EVIDENCE_ALT_REQUIRED");
       check(altRequired === !projected.descriptor.decorative, `${where}: alt rule judged a different asset than the one rendered`);
+
+      // 7. Instant Preview's own pair agrees with the mock adapter's. The two
+      //    are byte-parallel expressions in different layers (`presentation/`
+      //    may not import `adapters/`), and the pair regressed in three
+      //    separate fix rounds, so the agreement is asserted rather than
+      //    assumed. The single sanctioned divergence is the legacy static
+      //    key's `assetId`: with no Asset backing it, Instant Preview returns
+      //    a fixed literal where the adapter derives one from the static
+      //    registry. Everything else -- acceptance, path, dimensions,
+      //    mediaType, decorative -- must match exactly, and the divergence is
+      //    pinned so a future change cannot widen it unnoticed.
+      const previewDescriptor = resolveInstantPreviewAssetDescriptor(assets)(key);
+      const { assetId: previewAssetId, ...previewRest } = previewDescriptor;
+      const { assetId: mockAssetId, ...mockRest } = projected.descriptor as unknown as
+        Record<string, unknown> & { assetId: string };
+      check(
+        JSON.stringify(previewRest) === JSON.stringify(mockRest),
+        `${where}: Instant Preview descriptor differs from the adapter's beyond assetId (${JSON.stringify(previewRest)} vs ${JSON.stringify(mockRest)})`,
+      );
+      check(
+        /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/.test(previewAssetId),
+        `${where}: Instant Preview assetId is not a stable UUID (${previewAssetId})`,
+      );
+      check(
+        (previewAssetId === mockAssetId) === Boolean(assets.some((candidate) => candidate.assetKey === key && candidate.id === mockAssetId)),
+        `${where}: assetId agreement is not confined to the legacy fallback`,
+      );
+
+      // 8. Instant Preview's descriptor and the pixels it renders are one asset.
+      check(
+        pixels.src === previewDescriptor.publicPath,
+        `${where}: Instant Preview descriptor (${previewDescriptor.publicPath}) and pixels (${pixels.src}) disagree`,
+      );
+
+      // 9. Order independence holds for Instant Preview's resolver too.
+      check(
+        JSON.stringify(resolveInstantPreviewAssetDescriptor([...assets].reverse())(key)) ===
+          JSON.stringify(previewDescriptor),
+        `${where}: order-dependent Instant Preview descriptor`,
+      );
     }
   }
   assert.ok(checked >= 100, `only ${checked} combinations checked`);