test(e2e): make nine red specs assert the contracts the code actually implements

The e2e suite had never been run during this audit. It failed 9 of 256; seven of those
predated the audit's changes, established by building a stack from a clean HEAD worktree
and running the same specs against it rather than guessing.

Most were stale assertions rather than product defects:

- quota.spec solved for a target limit using the observed uploader count, but the divisor is
  max(active, estimated_guest_count, 1) and that config seeds at 100 — so every limit it
  aimed for came out 100x small and every "within quota" upload 413'd.
- rate-limit-shared-nat destructured `ticket` from a 429 body and fetched with
  `ticket=undefined`, turning the 429 under test into an unrelated 401. It also faked a
  release with no archive on disk, so the mint's pre-check 404'd and the per-day limiter was
  never reached; it now does a real release and asserts 200 rather than "not 429".
- ddos allowed only [200,429] from ten concurrent streams, so it failed on the very defence
  it exercises: four tickets per session survive and the rest correctly 401. Now asserts
  exactly four, which a tightened cap or an inverted eviction order would catch.
- auth-tampering asserted a throttled IP is refused EVEN with the correct password. That
  contract was deliberately removed — it let any phone on the venue NAT lock the operator
  out of their own admin panel, with a circular escape hatch. Inverted, plus a new check
  that a success does not refill an attacker's bucket.
- moderation-ui assumed a ban leaves a comment "stuck on screen"; `list_for_upload` filters
  banned authors, so it is hidden from everyone including the host. Now pins the pair that
  matters — the ban hides it, and the host's permanent removal survives an unban — and the
  UI leg it used to own is restored as a separate test on a reachable comment.

The export specs mint with `?kind=` now that a download ticket is bound to one archive, and
four of them assert the mint's 404 rather than the download's: with the kind always known,
the pre-check refuses up front instead of after charging a daily download for an archive
that cannot be served.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

e2e/specs/07-adversarial/auth-tampering.spec.ts

@@ -133,10 +133,14 @@ test.describe('Adversarial — PIN brute-force', () => {
       });
       statuses.push(r.status);
     }
-    expect(statuses.filter((s) => s === 200), 'a wrong PIN must never authenticate').toHaveLength(
-      0
-    );
-    expect(statuses.some((s) => s === 429), 'the attacker must be throttled').toBe(true);
+    expect(
+      statuses.filter((s) => s === 200),
+      'a wrong PIN must never authenticate'
+    ).toHaveLength(0);
+    expect(
+      statuses.some((s) => s === 429),
+      'the attacker must be throttled'
+    ).toBe(true);
 
     expect(
       await db.isPinLocked(g.userId),
@@ -255,29 +259,46 @@ test.describe('Adversarial — admin password brute-force', () => {
     expect(statuses.some((s) => s === 200)).toBe(false);
   });
 
-  test('once throttled, even the CORRECT admin password is refused (it is an IP limit, not a password check)', async ({
-    api,
-    adminToken,
-  }) => {
-    // This is the assertion that makes the test non-vacuous: it isolates the RATE LIMIT from the
-    // password logic. If the throttle were removed, the correct password would return 200 here.
+  test('the FAILURE bucket never refuses a correct admin password', async ({ api, adminToken }) => {
+    // This asserted the OPPOSITE — that a throttled IP is refused even with the right password —
+    // and that contract was deliberately removed, because at a real event it is a denial of
+    // service against the operator. Every guest at the venue shares one public IP behind NAT and
+    // `/admin/login` is a publicly linkable page, so a single tight IP bucket charged before the
+    // password check meant any phone in the room could keep it full and the host, on that same IP,
+    // could never spend a slot. The escape hatch was circular: `admin_login_rate_enabled` is only
+    // reachable through `PATCH /admin/config`, which needs the session being blocked.
+    //
+    // So the tight bucket is now charged ONLY on a wrong password. Brute force stays bounded (every
+    // guess costs a slot, per IP) while a valid credential is always honoured. A separate, generous
+    // per-IP ceiling bounds bcrypt CPU regardless of correctness — see ADMIN_LOGIN_CPU_CEILING.
     await api.patchConfig(adminToken, {
       rate_limits_enabled: 'true',
       admin_login_rate_enabled: 'true',
     });
 
-    // Exhaust the window with wrong passwords until throttled.
+    // Exhaust the failure window with wrong passwords until throttled.
     let throttled = false;
     for (let i = 0; i < 10 && !throttled; i++) {
       throttled = (await tryLogin('wrong-' + i)).status === 429;
     }
-    expect(throttled, 'the IP should be throttled after a burst').toBe(true);
+    expect(throttled, 'a burst of WRONG passwords from one IP must be rate-limited').toBe(true);
 
-    // The right password, while throttled, must STILL be refused — the limiter is checked before
-    // the bcrypt verify, so a valid credential does not buy a way around a brute-force lockout.
+    // The limiter is real (above) and yet the operator gets in. That combination is the whole
+    // property: THIS bucket keys on failure, not on the IP alone.
+    //
+    // Deliberately not claimed here: "guests cannot lock the host out". They still can — the
+    // separate CPU ceiling below refuses any password, correct included. This test stays under
+    // that ceiling on purpose so the two are not conflated.
     expect(
       (await tryLogin(ADMIN_PASSWORD)).status,
-      'a throttled IP is refused even with the correct password'
+      'a burst of wrong guesses must not cost the operator their own admin panel'
+    ).toBe(200);
+
+    // And guessing is still throttled AFTER a successful login — a correct password must not
+    // refill or bypass the attacker's bucket.
+    expect(
+      (await tryLogin('wrong-again')).status,
+      'a successful login must not clear the failure bucket for wrong guesses'
     ).toBe(429);
   });