Sprint D: hardening e2e, /search redirect, scroll restore fix.

Admin review smoke tests, CWV budgets, unified gallery at /, and explicit
body unlock when closing the photo modal so scroll position restores.

e2e/web-vitals-budgets.ts

@@ -0,0 +1,65 @@
+import { expect, type Page } from '@playwright/test';
+
+/**
+ * Core Web Vitals budget gates for the public viewer gallery.
+ * Generous for shared CI + DEV LXC — catches order-of-magnitude regressions.
+ */
+export const CWV_BUDGET = {
+  /** Largest Contentful Paint (ms) after navigation settles. */
+  lcp: 5_000,
+  /** Cumulative Layout Shift (unitless, 0–1+). */
+  cls: 0.2,
+} as const;
+
+export type WebVitalsSample = {
+  lcp: number;
+  cls: number;
+};
+
+/** Install observers before navigation (call once per test). */
+export async function installWebVitalsCollector(page: Page): Promise<void> {
+  await page.addInitScript(() => {
+    const w = window as Window & { __punimtagCwv?: WebVitalsSample };
+    w.__punimtagCwv = { lcp: 0, cls: 0 };
+
+    try {
+      new PerformanceObserver((list) => {
+        const entries = list.getEntries();
+        const last = entries[entries.length - 1] as PerformanceEntry & { startTime: number };
+        if (last) w.__punimtagCwv!.lcp = last.startTime;
+      }).observe({ type: 'largest-contentful-paint', buffered: true as boolean });
+    } catch {
+      /* unsupported */
+    }
+
+    try {
+      new PerformanceObserver((list) => {
+        for (const entry of list.getEntries()) {
+          const shift = entry as PerformanceEntry & { value?: number; hadRecentInput?: boolean };
+          if (shift.hadRecentInput) continue;
+          w.__punimtagCwv!.cls += shift.value ?? 0;
+        }
+      }).observe({ type: 'layout-shift', buffered: true as boolean });
+    } catch {
+      /* unsupported */
+    }
+  });
+}
+
+export async function readWebVitals(page: Page, settleMs = 2_000): Promise<WebVitalsSample> {
+  await page.waitForLoadState('domcontentloaded');
+  await page.waitForTimeout(settleMs);
+  return page.evaluate(() => {
+    const w = window as Window & { __punimtagCwv?: WebVitalsSample };
+    return w.__punimtagCwv ?? { lcp: 0, cls: 0 };
+  });
+}
+
+export function expectWithinCwvBudget(sample: WebVitalsSample): void {
+  expect(sample.lcp, `LCP ${Math.round(sample.lcp)}ms exceeds budget ${CWV_BUDGET.lcp}ms`).toBeLessThanOrEqual(
+    CWV_BUDGET.lcp,
+  );
+  expect(sample.cls, `CLS ${sample.cls.toFixed(3)} exceeds budget ${CWV_BUDGET.cls}`).toBeLessThanOrEqual(
+    CWV_BUDGET.cls,
+  );
+}