feat: F5.6c measured and accepted on test-filius; tickets up to 5 s ahead of F's clock

test-filius refused every ticket as from the future: its clock was 886 ms
behind the dashboard's machine, with NTP still 8 ms (one ticket in 125, as a
ticket carries whole seconds). F now takes a ticket signed up to 5 s ahead
(TICKET_AHEAD_SECONDS); itsdangerous refuses one second, and the oracle
keeps that on record.

tools/live measures and accepts on a live F, with fresh projects each run:
m3 (200 rooms of the largest example with pings: probe p95 37 ms), m4 (63 KB
document; dragging makes an update per pointer move, 59/s), m5 (an hour
through the proxy), acceptance (two browsers, 14 checks, passed three times)
and clock (F's clock against ours).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/live/m4.ts

@@ -0,0 +1,59 @@
+// M4 on a live server F: how large the shared document of the largest example
+// is, and how many updates dragging a device makes. Mia drags a device in a
+// real browser for two seconds at 60 pointer moves a second (as a finger or
+// a mouse does); a second person, watching through /sync, counts the updates
+// that arrive and their bytes. Then the document's size as F holds it: fresh,
+// after the drags, and as one update (what a new person loads).
+//
+//   npx vite-node tools/live/m4.ts
+
+import * as Y from 'yjs';
+import { chromium } from '@playwright/test';
+import { onDevice } from '../../packages/editor/browser/editorPage.js';
+import { cleanUp, joinDoc, seededProject, signIn, signInAddress } from './lib.js';
+
+const EXAMPLE = 'java-examples/Internet_Komplett_mit_eMail_Webserver_Intranet_Portforwarding_Firewall_DHCP_DE.fls';
+const MOVES_PER_SECOND = 60;
+const SECONDS = 2;
+
+const browser = await chromium.launch();
+try {
+  const { project, example } = await seededProject(EXAMPLE);
+  const watcher = await joinDoc(project, await signIn(project, { name: 'Zuschauer' }));
+  console.log(`fresh document: ${Y.encodeStateAsUpdate(watcher.doc).length} bytes, ${example.graph.nodes.length} devices, ${example.graph.links.length} cables`);
+  const page = await (await browser.newContext({ viewport: { width: 1400, height: 900 } })).newPage();
+  await page.goto(signInAddress(project, { name: 'Mia' }));
+  await page.waitForSelector('svg.filius-canvas');
+  const arrivals: { at: number; bytes: number }[] = [];
+  watcher.doc.on('update', (update: Uint8Array, origin: unknown) => {
+    if (origin !== null && typeof origin === 'object') arrivals.push({ at: performance.now(), bytes: update.length });
+  });
+  for (const name of ['Heimrouter', 'webserver.de (120.130.140.80)', 'iPad 1']) {
+    arrivals.length = 0;
+    const from = await onDevice(page, example.graph.nodes.find((node) => node.displayName === name)!.id);
+    await page.mouse.move(from.x, from.y);
+    await page.mouse.down();
+    const start = performance.now();
+    const moves = MOVES_PER_SECOND * SECONDS;
+    for (let step = 1; step <= moves; step++) {
+      await page.mouse.move(from.x + 150 * Math.sin((step / moves) * Math.PI), from.y + 80 * (step / moves));
+      const due = start + (step * 1000) / MOVES_PER_SECOND;
+      await new Promise((resolve) => setTimeout(resolve, Math.max(0, due - performance.now())));
+    }
+    await page.mouse.up();
+    const dragged = (performance.now() - start) / 1000;
+    await new Promise((resolve) => setTimeout(resolve, 1500));
+    const bytes = arrivals.reduce((sum, each) => sum + each.bytes, 0);
+    console.log(
+      `drag ${name.padEnd(30)} ${dragged.toFixed(1)} s: ${arrivals.length} updates (${(arrivals.length / dragged).toFixed(0)}/s), ${bytes} bytes, ${(bytes / Math.max(1, arrivals.length)).toFixed(0)} per update`,
+    );
+  }
+  console.log(`after the drags: ${Y.encodeStateAsUpdate(watcher.doc).length} bytes as one update`);
+  const fresh = await joinDoc(project, await signIn(project, { name: 'Neu' }));
+  console.log(`a new person loads: ${Y.encodeStateAsUpdate(fresh.doc).length} bytes`);
+  fresh.close();
+  watcher.close();
+} finally {
+  await browser.close();
+  await cleanUp();
+}