Exclude derived scene thumbnails from orphan findings

tests/scene-thumbnail-orphan-test.mjs

@@ -0,0 +1,30 @@
+import assert from "node:assert/strict";
+import { buildFindings, createFileRecord } from "../scripts/core/finding-engine.js";
+import { createFileLocator } from "../scripts/core/path-utils.js";
+
+const files = [
+  createFileRecord(createFileLocator("data", "worlds/demo-world/assets/scenes/exampleScene-thumb.webp"), 1234)
+];
+
+const references = [
+  {
+    sourceType: "world-document",
+    sourceScope: { ownerType: "world", ownerId: "demo-world", systemId: "demo-system", subtype: "actors" },
+    sourceLabel: "Actor demo",
+    rawValue: "worlds/demo-world/assets/actors/portrait.webp",
+    normalized: {
+      ...createFileLocator("data", "worlds/demo-world/assets/actors/portrait.webp"),
+      targetKind: "local-file"
+    }
+  }
+];
+
+const findings = buildFindings({ files, references });
+
+assert.equal(
+  findings.some(finding => finding.kind === "orphan-file" && finding.target.locator === "data:worlds/demo-world/assets/scenes/exampleScene-thumb.webp"),
+  false,
+  "derived scene thumbnails should not be reported as orphaned"
+);
+
+console.log("scene-thumbnail-orphan-test: ok");