chore: COD-28 harden dependencies and public assets

scripts/check-public-assets.mjs

@@ -0,0 +1,66 @@
+#!/usr/bin/env node
+
+import { execFileSync } from 'node:child_process';
+import { readdirSync, readFileSync } from 'node:fs';
+import { dirname, extname, join, relative, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const repoRoot = resolve(dirname(fileURLToPath(import.meta.url)), '..');
+const publicRoot = resolve(repoRoot, 'src/web/public');
+const prettierBin = resolve(repoRoot, 'node_modules/.bin/prettier');
+const checkedExtensions = new Set(['.js', '.css', '.html', '.json']);
+
+function collectTextAssets(dir) {
+  const files = [];
+  for (const entry of readdirSync(dir, { withFileTypes: true })) {
+    const fullPath = join(dir, entry.name);
+    if (entry.isDirectory()) {
+      files.push(...collectTextAssets(fullPath));
+      continue;
+    }
+    if (checkedExtensions.has(extname(entry.name))) {
+      files.push(fullPath);
+    }
+  }
+  return files;
+}
+
+function findNullByte(buffer) {
+  for (let i = 0; i < buffer.length; i += 1) {
+    if (buffer[i] === 0) return i;
+  }
+  return -1;
+}
+
+const files = collectTextAssets(publicRoot);
+const failures = [];
+
+for (const file of files) {
+  const rel = relative(repoRoot, file);
+  const data = readFileSync(file);
+  const nullByteIndex = findNullByte(data);
+  if (nullByteIndex !== -1) {
+    failures.push(`${rel}: contains literal NUL byte at offset ${nullByteIndex}`);
+  }
+
+  if (extname(file) === '.js') {
+    try {
+      execFileSync(process.execPath, ['--check', file], { cwd: repoRoot, stdio: 'pipe' });
+    } catch (err) {
+      failures.push(`${rel}: JavaScript syntax check failed\n${String(err.stderr || err.message).trim()}`);
+    }
+  }
+}
+
+try {
+  execFileSync(prettierBin, ['--check', ...files], { cwd: repoRoot, stdio: 'pipe' });
+} catch (err) {
+  failures.push(`Prettier public asset check failed\n${String(err.stdout || err.stderr || err.message).trim()}`);
+}
+
+if (failures.length > 0) {
+  console.error(failures.join('\n\n'));
+  process.exit(1);
+}
+
+console.log(`Public asset checks passed (${files.length} files).`);