chore(e2e): add ESLint + Prettier; fix real findings; dedupe BASE

The Playwright suite had no linter and no formatter — only tsc. Add flat-config ESLint
(typescript-eslint, type-aware) and Prettier (2-space, matching the suite's style).

Rules keep the ones that catch real TEST bugs and drop the noise:
  - no-floating-promises KEPT — an un-awaited request/assertion can let a test end before it runs,
    passing vacuously. It caught one: the SSE reader loop in sse-listener is now explicitly `void`.
  - no-unused-vars KEPT — caught three dead bindings (an unused adminToken fixture arg, an unused
    `api` arg, an unused JPEG_MAGIC import), all removed.
  - no-explicit-any OFF — all test code; `any` is the honest type for an untyped res.json() body or
    a page.evaluate() return.
  - no-empty-pattern OFF — Playwright's dependency-free fixtures are `async ({}, use) => {}`.

Refactor: `const BASE = process.env.E2E_FRONTEND_URL ?? '...'` was redeclared verbatim in 23
files — extracted to helpers/env.ts and imported, so a port/scheme change is one edit not a sweep.

Then `prettier --write`. Verified: eslint clean, tsc clean, prettier clean, desktop suite 210
passed / 1 skipped. (One mobile spec flaked once under retries:0 — a pre-existing cross-test
reflow-timing vector from the flakiness audit, not this change: the each-key edit is stable across
16 isolated runs and a clean full mobile re-run.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

e2e/specs/05-admin/authz-sweep.spec.ts

@@ -19,8 +19,7 @@
  * still download the keepsake) is BY DESIGN, and is asserted in 07-adversarial/authorization-deep.
  */
 import { test, expect } from '../../fixtures/test';
-
-const BASE = process.env.E2E_FRONTEND_URL ?? 'http://localhost:3101';
+import { BASE } from '../../helpers/env';
 
 type Method = 'GET' | 'POST' | 'PATCH' | 'DELETE';
 interface Route {
@@ -37,23 +36,66 @@ const ROUTES: Route[] = [
   { method: 'GET', path: () => '/api/v1/host/event', name: 'GET /host/event' },
   { method: 'POST', path: () => '/api/v1/host/event/close', name: 'POST /host/event/close' },
   { method: 'POST', path: () => '/api/v1/host/event/open', name: 'POST /host/event/open' },
-  { method: 'POST', path: () => '/api/v1/host/gallery/release', name: 'POST /host/gallery/release' },
+  {
+    method: 'POST',
+    path: () => '/api/v1/host/gallery/release',
+    name: 'POST /host/gallery/release',
+  },
   { method: 'POST', path: () => '/api/v1/host/export/rebuild', name: 'POST /host/export/rebuild' },
   { method: 'GET', path: () => '/api/v1/host/users', name: 'GET /host/users' },
-  { method: 'POST', path: (v) => `/api/v1/host/users/${v}/ban`, name: 'POST /host/users/{id}/ban', body: {} },
-  { method: 'POST', path: (v) => `/api/v1/host/users/${v}/unban`, name: 'POST /host/users/{id}/unban', body: {} },
-  { method: 'PATCH', path: (v) => `/api/v1/host/users/${v}/role`, name: 'PATCH /host/users/{id}/role', body: { role: 'host' } },
-  { method: 'POST', path: (v) => `/api/v1/host/users/${v}/pin-reset`, name: 'POST /host/users/{id}/pin-reset', body: {} },
-  { method: 'GET', path: () => '/api/v1/host/pin-reset-requests', name: 'GET /host/pin-reset-requests' },
-  { method: 'DELETE', path: (v) => `/api/v1/host/pin-reset-requests/${v}`, name: 'DELETE /host/pin-reset-requests/{id}' },
+  {
+    method: 'POST',
+    path: (v) => `/api/v1/host/users/${v}/ban`,
+    name: 'POST /host/users/{id}/ban',
+    body: {},
+  },
+  {
+    method: 'POST',
+    path: (v) => `/api/v1/host/users/${v}/unban`,
+    name: 'POST /host/users/{id}/unban',
+    body: {},
+  },
+  {
+    method: 'PATCH',
+    path: (v) => `/api/v1/host/users/${v}/role`,
+    name: 'PATCH /host/users/{id}/role',
+    body: { role: 'host' },
+  },
+  {
+    method: 'POST',
+    path: (v) => `/api/v1/host/users/${v}/pin-reset`,
+    name: 'POST /host/users/{id}/pin-reset',
+    body: {},
+  },
+  {
+    method: 'GET',
+    path: () => '/api/v1/host/pin-reset-requests',
+    name: 'GET /host/pin-reset-requests',
+  },
+  {
+    method: 'DELETE',
+    path: (v) => `/api/v1/host/pin-reset-requests/${v}`,
+    name: 'DELETE /host/pin-reset-requests/{id}',
+  },
   { method: 'DELETE', path: (v) => `/api/v1/host/upload/${v}`, name: 'DELETE /host/upload/{id}' },
   { method: 'DELETE', path: (v) => `/api/v1/host/comment/${v}`, name: 'DELETE /host/comment/{id}' },
 
   // ── Admin surface ───────────────────────────────────────────────────────
   { method: 'GET', path: () => '/api/v1/admin/stats', name: 'GET /admin/stats', adminOnly: true },
   { method: 'GET', path: () => '/api/v1/admin/config', name: 'GET /admin/config', adminOnly: true },
-  { method: 'PATCH', path: () => '/api/v1/admin/config', name: 'PATCH /admin/config', adminOnly: true, body: { quota_enabled: 'false' } },
-  { method: 'GET', path: () => '/api/v1/admin/export/jobs', name: 'GET /admin/export/jobs', adminOnly: true },
+  {
+    method: 'PATCH',
+    path: () => '/api/v1/admin/config',
+    name: 'PATCH /admin/config',
+    adminOnly: true,
+    body: { quota_enabled: 'false' },
+  },
+  {
+    method: 'GET',
+    path: () => '/api/v1/admin/export/jobs',
+    name: 'GET /admin/export/jobs',
+    adminOnly: true,
+  },
 ];
 
 async function call(route: Route, jwt: string, victimId: string): Promise<number> {
@@ -89,7 +131,10 @@ test.describe('Authorization sweep — every privileged route', () => {
 
       const status = await call(route, host.jwt, victim.userId);
 
-      expect(status, `${route.name} is admin-only and must reject a host with 403, got ${status}`).toBe(403);
+      expect(
+        status,
+        `${route.name} is admin-only and must reject a host with 403, got ${status}`
+      ).toBe(403);
     });
   }
 
@@ -121,9 +166,10 @@ test.describe('Authorization sweep — every privileged route', () => {
         headers: route.body !== undefined ? { 'Content-Type': 'application/json' } : {},
         ...(route.body !== undefined ? { body: JSON.stringify(route.body) } : {}),
       });
-      expect([401, 403], `${route.name} must reject an anonymous caller, got ${res.status}`).toContain(
-        res.status
-      );
+      expect(
+        [401, 403],
+        `${route.name} must reject an anonymous caller, got ${res.status}`
+      ).toContain(res.status);
     }
   });
 });