Replace waitForLoadState("networkidle") in e2e helpers

The SSE connection to /api/events (added with notifications) keeps the
network in-flight forever, so `networkidle` never resolves. Each save
in the affected helpers timed out at 30s × 3 retries, which both broke
the run and made it suspiciously long.

Switched to explicit waits:
- "Profile saved." text after settings save (notifications + public-content + social)
- "No pending follow requests." after Approve (social.test.ts)
- toBeHidden poll for the Mark all read button (notifications)
- toBeVisible poll for the empty-state copy after Approve (notifications)

These are all the affected `networkidle` call sites in e2e. The
fetcher.Form pattern stays — once the action commits, the page
revalidates and the post-state element appears.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

e2e/public-content.test.ts

@@ -58,7 +58,10 @@ async function setProfileVisibilityPublic(page: Page) {
   await page.goto("/settings");
   await page.locator('input[type=radio][name=profileVisibility][value=public]').check();
   await page.getByRole("button", { name: /^Save$/ }).first().click();
-  await page.waitForLoadState("networkidle");
+  // Don't wait for networkidle — the SSE connection to /api/events
+  // (added with notifications) keeps the network in-flight forever.
+  // Wait for the explicit save confirmation instead.
+  await expect(page.getByText("Profile saved.")).toBeVisible({ timeout: 10000 });
 }
 
 // Registration + WebAuthn virtual authenticator can race under parallel