chore(perf): add nip-07/relay diagnostic harnesses + dev REQ monitor

Headless Playwright probes that reproduce the real login path via a fake
window.nostr extension (which loginWithNsec bypasses) and measure
steady-state extension-call and relay-REQ rates:
- nip07-heat.mjs, req-capture.mjs, ws-lifecycle.mjs, loopc-capture.mjs, etc.

Plus js/devReqMonitor.js: a localhost-only WebSocket REQ-rate monitor that
warns in-console when relay traffic spikes, naming the storming kinds — used
to capture the real-environment storm the mock-relay harness could not see.
Removable once the refactor lands.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

scripts/perf/disclaimer-grid.mjs

@@ -0,0 +1,58 @@
+// Reproduces the logged-out "videos don't load until refresh after dismissing
+// the disclaimer" bug. Fresh context (no hasSeenDisclaimer), real relays.
+//
+// Usage: APP=http://localhost:3000 node scripts/perf/disclaimer-grid.mjs
+
+import { chromium } from "playwright";
+
+const APP = process.env.APP || "http://localhost:3000";
+
+const cardCount = (page) =>
+  page.evaluate(() => document.querySelectorAll("[data-video-id],[data-video-card]").length);
+
+const browser = await chromium.launch({ headless: true });
+const ctx = await browser.newContext(); // fresh: no hasSeenDisclaimer
+const page = await ctx.newPage();
+const logs = [];
+page.on("console", (m) => logs.push(`[${m.type()}] ${m.text()}`.slice(0, 160)));
+page.on("pageerror", (e) => logs.push(`[pageerror] ${String(e).split("\n")[0]}`));
+
+await page.goto(APP, { waitUntil: "domcontentloaded", timeout: 30000 });
+
+// Wait for disclaimer modal to appear.
+await page.waitForTimeout(3000);
+const hadDisclaimer = await page.evaluate(() => {
+  const m = document.getElementById("disclaimerModal");
+  return !!m && getComputedStyle(m).display !== "none" && m.offsetParent !== null;
+});
+const beforeDismiss = await cardCount(page);
+
+// Dismiss the disclaimer (click its primary/accept button).
+let clicked = false;
+try {
+  const btn = page.locator('#disclaimerModal button, [data-testid="disclaimer-accept"]').first();
+  if (await btn.count()) { await btn.click({ timeout: 4000 }); clicked = true; }
+} catch (_) {}
+
+await page.waitForTimeout(6000);
+const afterDismiss = await cardCount(page);
+
+// Now reload and re-check (the "refresh fixes it" path).
+await page.reload({ waitUntil: "domcontentloaded" });
+await page.waitForTimeout(6000);
+const afterReload = await cardCount(page);
+
+await browser.close();
+
+console.log("\n=== DISCLAIMER → GRID ===");
+console.log(`disclaimer shown:        ${hadDisclaimer}`);
+console.log(`cards before dismiss:    ${beforeDismiss}`);
+console.log(`dismiss clicked:         ${clicked}`);
+console.log(`cards after dismiss:     ${afterDismiss}   <- BUG if 0`);
+console.log(`cards after reload:      ${afterReload}    <- if >0 here but 0 above = the reported bug`);
+const interesting = logs.filter((l) => /error|fail|grid|render|feed|disclaimer/i.test(l));
+if (interesting.length) {
+  console.log("\nrelevant logs:");
+  for (const l of interesting.slice(0, 15)) console.log("  " + l);
+}
+console.log("");