rescue: in-flight lane work, saved when the session limit killed every agent

Committed verbatim, unreviewed and unverified. Original branch: main.
Saved because uncommitted work on no ref is one checkout from gone — that
happened once already today to 463 lines of buildkitd cutover.

pkg/ui/shot.cjs

@@ -0,0 +1,66 @@
+// Capture mobile + desktop fullPage screenshots of a URL.
+// usage: node shot.cjs <url> <outPrefix>
+const { chromium } = require('@playwright/test');
+
+const [url, outPrefix] = process.argv.slice(2);
+if (!url || !outPrefix) {
+  console.error('usage: node shot.cjs <url> <outPrefix>');
+  process.exit(2);
+}
+
+const VIEWS = [
+  { name: 'mobile', width: 390, height: 844 },
+  { name: 'desktop', width: 1440, height: 900 },
+];
+
+(async () => {
+  const browser = await chromium.launch();
+  const errors = [];
+  for (const v of VIEWS) {
+    const ctx = await browser.newContext({
+      viewport: { width: v.width, height: v.height },
+      deviceScaleFactor: 2,
+    });
+    const page = await ctx.newPage();
+    page.on('console', (m) => {
+      if (m.type() === 'error') errors.push(`[${v.name}] console: ${m.text()}`);
+    });
+    page.on('pageerror', (e) => errors.push(`[${v.name}] pageerror: ${e.message}`));
+
+    const resp = await page.goto(url, { waitUntil: 'networkidle', timeout: 45000 });
+    await page.waitForTimeout(1200);
+
+    const out = `${outPrefix}-${v.name}.png`;
+    await page.screenshot({ path: out, fullPage: true });
+
+    // report what actually rendered, so a blank page can't pass silently
+    const info = await page.evaluate(() => {
+      const b = document.body;
+      const bg = getComputedStyle(b).backgroundColor;
+      const html = getComputedStyle(document.documentElement).backgroundColor;
+      return {
+        bodyBg: bg,
+        htmlBg: html,
+        textLen: (b.innerText || '').trim().length,
+        nodes: b.querySelectorAll('*').length,
+        rootChildren: (document.getElementById('root') || b).children.length,
+        title: document.title,
+        sample: (b.innerText || '').trim().slice(0, 180).replace(/\s+/g, ' '),
+      };
+    });
+    console.log(
+      `${v.name}: status=${resp && resp.status()} -> ${out}\n` +
+        `   title=${JSON.stringify(info.title)} bodyBg=${info.bodyBg} htmlBg=${info.htmlBg}\n` +
+        `   domNodes=${info.nodes} rootChildren=${info.rootChildren} textLen=${info.textLen}\n` +
+        `   text="${info.sample}"`
+    );
+    await ctx.close();
+  }
+  await browser.close();
+  if (errors.length) {
+    console.log('--- page errors ---');
+    for (const e of errors.slice(0, 25)) console.log('   ' + e);
+  } else {
+    console.log('--- no console/page errors ---');
+  }
+})();