test(e2e): update suite for shipped features + gate Chromium-only perms

The running test container had been built from an older tree; rebuilding it to
pick up current app code surfaced several tests that predated shipped
security/UX features:

- file-upload-attacks / rate-limit: assert the magic-byte rejection wording and
  upload a real decodable JPEG (a zero-buffer is now rejected at the boundary).
- ddos: open SSE via the single-use /stream/ticket flow, not the dead ?token=.
- recover-page / join: the PIN field auto-submits on the 4th digit, so don't
  race an explicit submit click against the ensuing navigation.
- gestures-doubletap / sheet-escape: target the lightbox by aria-labelledby and
  anchor the radio accessible-name match at the start (gated dialog semantics).

playwright.config: camera/mic/clipboard are Chromium-only permissions (they threw
"Unknown permission: camera" on firefox/webkit and failed the test at context
creation); grant them per-Chromium-project. firefox-android drops the
unsupported isMobile flag.

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

e2e/playwright.config.ts

@@ -12,6 +12,12 @@ import { defineConfig, devices } from '@playwright/test';
  * engine-level divergences. The rest of the suite only runs against
  * `chromium-desktop` to keep the wall-clock reasonable.
  */
+// camera/microphone/clipboard are Chromium-only permissions; passing them to
+// firefox/webkit projects throws "Unknown permission: camera" and fails the
+// whole test before it runs. Granted per-Chromium-project below instead of in
+// the global `use` block.
+const CHROMIUM_PERMISSIONS = ['camera', 'microphone', 'clipboard-read', 'clipboard-write'];
+
 export default defineConfig({
   testDir: './specs',
   outputDir: './test-results',
@@ -35,9 +41,8 @@ export default defineConfig({
     video: 'retain-on-failure',
     actionTimeout: 10_000,
     navigationTimeout: 30_000,
-    // Camera/mic permissions granted by default; the fake-media launch args
-    // (set per-project below for Chromium) supply the actual stream.
-    permissions: ['camera', 'microphone', 'clipboard-read', 'clipboard-write'],
+    // No camera/mic/clipboard here — those are Chromium-only and are granted on
+    // the Chromium projects below (see CHROMIUM_PERMISSIONS).
   },
 
   projects: [
@@ -49,6 +54,7 @@ export default defineConfig({
       testIgnore: ['**/09-mobile/**'],
       use: {
         ...devices['Desktop Chrome'],
+        permissions: CHROMIUM_PERMISSIONS,
         launchOptions: {
           args: [
             '--use-fake-ui-for-media-stream',
@@ -68,13 +74,13 @@ export default defineConfig({
     {
       name: 'chromium-mobile',
       testMatch: ['**/09-mobile/**/*.spec.ts'],
-      use: { ...devices['Pixel 7'] },
+      use: { ...devices['Pixel 7'], permissions: CHROMIUM_PERMISSIONS },
     },
 
     // ── Mobile UA smoke matrix (runs only @smoke specs in CI) ────────────
     {
       name: 'chromium-pixel7',
-      use: { ...devices['Pixel 7'] },
+      use: { ...devices['Pixel 7'], permissions: CHROMIUM_PERMISSIONS },
       grep: /@smoke/,
     },
     {
@@ -84,6 +90,7 @@ export default defineConfig({
         viewport: { width: 360, height: 780 },
         userAgent:
           'Mozilla/5.0 (Linux; Android 14; SM-S911B) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Mobile Safari/537.36',
+        permissions: CHROMIUM_PERMISSIONS,
       },
       grep: /@smoke/,
     },
@@ -94,6 +101,7 @@ export default defineConfig({
         viewport: { width: 360, height: 780 },
         userAgent:
           'Mozilla/5.0 (Linux; Android 14; SM-S911B) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/24.0 Chrome/124.0.0.0 Mobile Safari/537.36',
+        permissions: CHROMIUM_PERMISSIONS,
       },
       grep: /@smoke/,
     },
@@ -103,6 +111,7 @@ export default defineConfig({
         ...devices['Pixel 7'],
         userAgent:
           'Mozilla/5.0 (Linux; Android 14; Pixel 7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Mobile Safari/537.36 EdgA/124.0.0.0',
+        permissions: CHROMIUM_PERMISSIONS,
       },
       grep: /@smoke/,
     },
@@ -125,6 +134,9 @@ export default defineConfig({
       use: {
         ...devices['Pixel 7'],
         defaultBrowserType: 'firefox',
+        // Firefox rejects `isMobile` (Chromium-only). Keep the phone viewport +
+        // Android UA for coverage, but drop the unsupported flag.
+        isMobile: false,
         userAgent:
           'Mozilla/5.0 (Android 14; Mobile; rv:124.0) Gecko/124.0 Firefox/124.0',
       },