fix: preserve approved assets when adding project media

scripts/lib/merge-assets.mjs

@@ -0,0 +1,37 @@
+const idPattern = /^[a-z][a-z0-9-]{0,63}$/u;
+const fileNamePattern = /^[a-z0-9][a-z0-9-]*\.(avif|jpg|png|svg|webp|mp4|webm|opus|mp3)$/u;
+const sha256Pattern = /^[a-f0-9]{64}$/u;
+
+const assertSafeRecord = (asset) => {
+  if (!asset || typeof asset !== 'object' || Array.isArray(asset) ||
+    typeof asset.id !== 'string' || !idPattern.test(asset.id) ||
+    typeof asset.fileName !== 'string' || !fileNamePattern.test(asset.fileName) ||
+    typeof asset.sha256 !== 'string' || !sha256Pattern.test(asset.sha256)) {
+    throw new Error('ASSET-MERGE-RECORD-001');
+  }
+};
+
+export const mergeAssetRecords = (baseAssets, generatedAssets, managedIds) => {
+  if (!Array.isArray(baseAssets) || !Array.isArray(generatedAssets) || !(managedIds instanceof Set)) {
+    throw new Error('ASSET-MERGE-RECORD-001');
+  }
+  for (const asset of [...baseAssets, ...generatedAssets]) {
+    if (!asset || typeof asset !== 'object' || Array.isArray(asset) ||
+      typeof asset.id !== 'string' || typeof asset.fileName !== 'string') {
+      throw new Error('ASSET-MERGE-RECORD-001');
+    }
+  }
+  const retained = baseAssets.filter(({ id }) => !managedIds.has(id));
+  const combined = [...retained, ...generatedAssets];
+  const ids = new Set();
+  const names = new Set();
+  for (const asset of combined) {
+    const folded = asset.fileName.toLocaleLowerCase('en-US');
+    if (ids.has(asset.id)) throw new Error('ASSET-MERGE-ID-001');
+    if (names.has(folded)) throw new Error('ASSET-MERGE-NAME-001');
+    ids.add(asset.id);
+    names.add(folded);
+  }
+  for (const asset of [...baseAssets, ...generatedAssets]) assertSafeRecord(asset);
+  return combined.sort((left, right) => left.fileName.localeCompare(right.fileName, 'en-US'));
+};