Sound was dead in the app because status 0 is not a failure; and back is a swipe to the RIGHT

Oliver on the first shell build: *"I don't hear any of the games sounds.. daniel the umpire is
synthesized which is horrible and no music is playing on start"* — two independent causes.

- **Opaque fetch.** Capacitor serves the bundle through a custom WKURLSchemeHandler, and `fetch`
  reports those responses as `status: 0, ok: false` with the whole body present and decoding
  perfectly. All three loads in `audio.js` guarded with `if (!r.ok) throw`, so inside the app every
  recorded sound failed at the door: the umpire fell through to the synthesized `say()`, no bed
  started, no sample played. The synthesized sfx kept working, which made it read as a mixing bug
  rather than a loader one. Fixed once, in the shared `bytes()` helper every audio fetch now routes
  through — a status of 0 is the ABSENCE of an HTTP status, so trust it only when there is one and
  a real 404 still falls back. Any future `!r.ok` on a bundle-relative fetch is this same bug.
- **The ring switch.** WKWebView's WebAudio runs in the SoloAmbient session, which the hardware
  silent switch mutes outright — a silent game on a phone that lives on silent, with nothing on
  screen to explain it. AppDelegate now sets AVAudioSession `.playback`, the games category.

Confirmed in the shell: the bed reaches PLAYING, the context is `running` with no gesture at all
(autoplay really is allowed in WKWebView, as LATER predicted), and `say()` never fires. On the web,
a genuinely missing file still falls back — checked both.

And the swipe flips: **right goes back**, the way iOS's own pop gesture goes (*"that's the iOS
way"*). Left now does nothing. Noted in PROJECT.md that on a platform gesture the platform's
convention beats the literal wording of the brief, and that is worth saying up front.

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

ios/App/App/AppDelegate.swift

@@ -1,5 +1,6 @@
 import UIKit
 import Capacitor
+import AVFoundation
 
 @UIApplicationMain
 class AppDelegate: UIResponder, UIApplicationDelegate {
@@ -7,7 +8,14 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     var window: UIWindow?
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
-        // Override point for customization after application launch.
+        // PLAY THROUGH THE RING SWITCH. WKWebView's WebAudio runs in the SoloAmbient session by
+        // default, which the hardware silent switch mutes outright — so a phone that lives on silent
+        // (most of them) gets a completely silent game and nothing on screen explains why. `.playback`
+        // is the games-and-media category: audible on silent, and it is what makes the umpire and the
+        // menu theme reach a real device at all. The web build has no say in this; it is the whole
+        // reason the shell is worth having for sound. See PROJECT.md, "What the shell buys".
+        try? AVAudioSession.sharedInstance().setCategory(.playback)
+        try? AVAudioSession.sharedInstance().setActive(true)
         return true
     }