test(e2e): run the net on WebKit and an iPad profile; opt the account out of Home

The Playwright net now runs every flow in three projects: chromium (Desktop
Chrome), webkit (Desktop Safari) and ipad (iPad gen 7 landscape: touch, mobile
viewport). WebKit catches the engine-level differences every iOS browser
inherits; the config and the README say plainly what it does NOT catch: iPad
media refusals. Playwright's WebKit decodes through the host OS, and on Windows
it played an mp3-in-mp4 and an AV1 mp4 that a real iPad refuses, so media
formats are checked on a real iPad against the dev stack over the LAN.

global.setup opts the e2e account out of starting on Home (the Startup setting),
which the feed, channel and player specs need since E24. It only takes effect
with the new-tab boot fix: before it, all twelve of those specs landed on Home
in every project. 49/49 green on :8080 across the three projects.

frontend/playwright.config.ts

@@ -47,5 +47,19 @@ export default defineConfig({
       use: { ...devices["Desktop Chrome"], storageState: STORAGE_STATE },
       dependencies: ["setup"],
     },
+    // WebKit catches engine-level differences (JS, CSS/layout, event order) that every iOS browser
+    // inherits. It does NOT reproduce iPad MEDIA refusals: Playwright's WebKit decodes through the
+    // host OS (Media Foundation on Windows, GStreamer on Linux), and measured on 2026-09-14 it played
+    // an mp3-in-mp4 and an AV1 mp4 that iPad refuses. Media checks need a real iPad.
+    {
+      name: "webkit",
+      use: { ...devices["Desktop Safari"], storageState: STORAGE_STATE },
+      dependencies: ["setup"],
+    },
+    {
+      name: "ipad",
+      use: { ...devices["iPad (gen 7) landscape"], storageState: STORAGE_STATE },
+      dependencies: ["setup"],
+    },
   ],
 });