feat(android): align native preview with measured PWA design

scripts/compare-native-pwa.mjs

@@ -0,0 +1,53 @@
+// Development-only side-by-side evidence. This deliberately asserts no pixel parity.
+import fs from 'node:fs';
+import path from 'node:path';
+import { createRequire } from 'node:module';
+import { createHash } from 'node:crypto';
+
+const [modulePath, nativeDirectory, pwaDirectory, destination] = process.argv.slice(2);
+if (!destination) throw new Error('Usage: node compare-native-pwa.mjs PLAYWRIGHT_MODULE NATIVE_DIR PWA_DIR OUTPUT_DIR');
+const { chromium } = createRequire(import.meta.url)(path.resolve(modulePath));
+const viewport = JSON.parse(fs.readFileSync(path.join(nativeDirectory, 'viewport.json')));
+if (viewport.fontScale !== 1) throw new Error('This CSS reference comparison requires fontScale 1');
+const cssWidth = viewport.widthPx / viewport.density;
+const cssHeight = viewport.heightPx / viewport.density;
+const reference = JSON.parse(fs.readFileSync(path.join(pwaDirectory, 'measurements.json')));
+if (!reference.screens.every(screen => screen.viewport.width === cssWidth && screen.viewport.height === cssHeight)) {
+  throw new Error('PWA and native content viewports do not match');
+}
+function image(directory, name) {
+  const bytes = fs.readFileSync(path.join(directory, name));
+  if (bytes.subarray(0, 8).toString('hex') !== '89504e470d0a1a0a' ||
+      bytes.readUInt32BE(16) !== viewport.widthPx || bytes.readUInt32BE(20) !== viewport.heightPx) {
+    throw new Error(`Invalid or mismatched PNG: ${name}`);
+  }
+  return { uri: `data:image/png;base64,${bytes.toString('base64')}`, sha256: createHash('sha256').update(bytes).digest('hex') };
+}
+fs.mkdirSync(destination, { recursive: true });
+const browser = await chromium.launch({ headless: true, args: process.getuid?.() === 0 ? ['--no-sandbox'] : [] });
+const records = [];
+try {
+  const page = await browser.newPage({ viewport: { width: viewport.widthPx * 2, height: viewport.heightPx + 48 }, deviceScaleFactor: 1 });
+  await page.route('**/*', route => route.abort());
+  for (const name of ['login', 'dashboard', 'tasks', 'notes', 'shopping']) {
+    for (const theme of ['light', 'dark']) {
+      const native = image(nativeDirectory, `${name}-${theme}.png`);
+      const pwa = image(pwaDirectory, `${name}-${theme}-${cssWidth}.png`);
+      await page.setContent(`<meta http-equiv="Content-Security-Policy" content="default-src 'none'; img-src data:; style-src 'unsafe-inline'">
+        <style>body{margin:0;background:#eee;font:20px sans-serif}main{display:flex}section{width:${viewport.widthPx}px}
+        header{height:48px;display:grid;place-items:center}img{display:block;width:100%}</style>
+        <main><section><header>PWA 2.78.0 · ${name} · ${theme}</header><img src="${pwa.uri}"></section>
+        <section><header>Android nativ · ${name} · ${theme} · keine 1:1-Abnahme</header><img src="${native.uri}"></section></main>`);
+      await page.locator('img').evaluateAll(images => Promise.all(images.map(image => image.decode())));
+      const file = `${name}-${theme}-comparison.png`;
+      await page.screenshot({ path: path.join(destination, file) });
+      records.push({ file, nativeSha256: native.sha256, pwaSha256: pwa.sha256 });
+    }
+  }
+} finally {
+  await browser.close();
+}
+fs.writeFileSync(path.join(destination, 'comparison.json'), JSON.stringify({
+  status: 'Side-by-side evidence only; no visual acceptance', viewport, upstreamRevision: reference.upstreamRevision, records,
+}, null, 2) + '\n');
+console.log(`Wrote ${records.length} matched-viewport comparisons; no parity assertion.`);