Relocate JavaScript coverage export under web (#266)

web/scripts/export-coverage.js

@@ -0,0 +1,45 @@
+import { promises as fs } from 'node:fs';
+import path from 'node:path';
+
+const coverageDir = 'coverage';
+const reportsDir = 'reports';
+const outputPath = path.join(reportsDir, 'javascript-coverage.json');
+
+async function ensureReportsDir() {
+  try {
+    await fs.mkdir(reportsDir, { recursive: true });
+  } catch (error) {
+    console.error('Failed to ensure reports directory', error);
+    process.exit(1);
+  }
+}
+
+async function copyLatestCoverage() {
+  let entries;
+  try {
+    entries = await fs.readdir(coverageDir);
+  } catch (error) {
+    if (error.code === 'ENOENT') {
+      console.warn('Coverage directory not found; skipping export.');
+      return;
+    }
+    throw error;
+  }
+
+  const coverageFiles = entries.filter(name => name.endsWith('.json'));
+  if (!coverageFiles.length) {
+    console.warn('No coverage files generated; skipping export.');
+    return;
+  }
+
+  // Sort to pick the most recent entry deterministically.
+  coverageFiles.sort();
+  const latest = coverageFiles[coverageFiles.length - 1];
+  const source = path.join(coverageDir, latest);
+
+  await fs.copyFile(source, outputPath);
+  console.log(`Copied coverage report to ${outputPath}`);
+}
+
+await ensureReportsDir();
+await copyLatestCoverage();