Fix Playwright coverage collection and merge

e2e/fixtures.ts

@@ -0,0 +1,45 @@
+import fs from 'fs/promises';
+import path from 'path';
+import type { TestInfo } from '@playwright/test';
+import { expect, test as base, Page } from '@bgotink/playwright-coverage';
+
+const coverageDir = path.join(process.cwd(), 'coverage-reports', 'e2e', '.nyc_output');
+
+async function writeCoverageFile(page: Page, testInfo: TestInfo) {
+  try {
+    const coverage = await page.evaluate(() => (globalThis as any).__coverage__ ?? null);
+    if (!coverage || Object.keys(coverage).length === 0) return;
+
+    await fs.mkdir(coverageDir, { recursive: true });
+
+    const titleParts =
+      typeof testInfo.titlePath === 'function'
+        ? testInfo.titlePath()
+        : Array.isArray((testInfo as any).titlePath)
+          ? (testInfo as any).titlePath
+          : [testInfo.title];
+    const safeTitle = titleParts
+      .filter(Boolean)
+      .map((part) => part.replace(/[^a-zA-Z0-9-_]+/g, '_'))
+      .join('--')
+      .slice(0, 200);
+    const worker = typeof testInfo.workerIndex === 'number' ? `w${testInfo.workerIndex}` : 'w';
+    const filename = path.join(coverageDir, `coverage-${worker}-${Date.now()}-${safeTitle || 'test'}.json`);
+
+    await fs.writeFile(filename, JSON.stringify(coverage));
+    console.log('Wrote coverage file:', path.relative(process.cwd(), filename));
+  } catch (error) {
+    const msg = error instanceof Error ? error.message : String(error);
+    console.warn('Failed to collect coverage from page:', msg);
+  }
+}
+
+export const test = base.extend({
+  page: async ({ page }, use, testInfo) => {
+    await use(page);
+    await writeCoverageFile(page, testInfo);
+  },
+});
+
+export { expect };
+export type { Page };