feat(apple): gamepad UI v2 — controller settings + add host, aurora, macOS

Sources reorganized (client: Home/Session/Settings/Stores/Support/Trust; kit:
Audio/Connection/Gamepad/Input/Support/Video/Views) with the big files split
along the same seams.

The gamepad mode is couch-complete, and now on macOS too (the living-room
Mac case), not just iOS/iPadOS:

- GamepadSettingsView: a console-style, fully controller-navigable settings
  screen (X from the launcher) — up/down moves focus, left/right steps values
  (clamped, boundary thud), A cycles/toggles, B closes; the focused row shows a
  one-line description. Backed by GamepadMenuList, the vertical sibling of
  GamepadCarousel, and SettingsOptions — the option lists hoisted out of
  SettingsView statics and shared by the touch, tvOS and gamepad settings.
- GamepadAddHostView + GamepadKeyboard: register a host end to end with a pad
  — field rows open an on-screen controller keyboard (dpad grid, A types,
  X backspaces, B done); the launcher carousel ends in an Add Host tile, so
  the dead-end "add one with touch first" empty state is gone.
- Launcher polish: contextual hint bar with the pad's real button glyphs,
  controller name + battery chip, one shared console chrome.
- GamepadScreenBackground: an animated aurora (TimelineView-driven drifting
  blobs in the brand's violet family, breathing radii, slow hue shift,
  legibility scrim; freezes under Reduce Motion). Pure SwiftUI on purpose — a
  .metal library only bundles reliably in one of the two build systems (SPM vs
  the xcodeproj's synced folders) these sources compile under.
- macOS port: settings/add-host/library present as sized sheets (a macOS sheet
  takes its content's IDEAL size, and the GeometryReader-driven screens
  collapsed to nothing), NSScreen-based mode lists, scroll indicators .never
  (the "always show scroll bars" setting overrides .hidden), tray scrims so
  scrolled rows dim under the pinned title/hints, extra title clearance, and a
  PUNKTFUNK_FORCE_GAMEPAD_UI=1 dev hook — launcher/settings/add-host/keyboard/
  library render-verified live on a real Mac + LAN hosts.
- GamepadMenuInput: X button support, and (re)start now snapshots held buttons
  so a controller handoff press never fires twice (the B that closed the
  keyboard no longer also cancels the screen underneath).
- Cleanups: one "Connection failed" alert in ContentView instead of one per
  home screen; HostDiscovery.advertises/unsaved shared by both home screens.
- host: can_encode_444 stub for the non-Linux/Windows host build (the macOS
  synthetic-source loopback used by the Swift tests).

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

clients/apple/Sources/PunktfunkKit/Gamepad/GamepadUIEnvironment.swift

@@ -0,0 +1,26 @@
+// Whether the iOS/iPadOS/macOS UI should be in its controller-friendly mode (the console-style
+// host launcher, gamepad settings, and the coverflow library browser instead of the touch/desktop
+// layouts). A pure function, not a singleton: the reactivity comes from callers already observing
+// `GamepadManager.shared` and the `DefaultsKey.gamepadUIEnabled` @AppStorage themselves (the same
+// local-read pattern SettingsView already uses for GamepadManager), so this stays the single place
+// the two combine without adding a second ObservableObject or an environment key nobody else needs.
+
+import Foundation
+
+public enum GamepadUIEnvironment {
+    /// `enabledSetting` is the user's Settings toggle (`DefaultsKey.gamepadUIEnabled`);
+    /// `gamepadConnected` is `GamepadManager.shared.active != nil` — active only once a usable
+    /// controller is actually attached (a non-extended-profile device leaves `active` nil, which
+    /// keeps the touch UI). A `Bool` rather than the `DiscoveredController` itself: this function's
+    /// whole job is the AND, so there's nothing else to inspect, and it keeps the helper testable
+    /// without a real `GCController` (which XCTest can't construct).
+    public static func isActive(gamepadConnected: Bool, enabledSetting: Bool) -> Bool {
+        enabledSetting && (gamepadConnected || forced)
+    }
+
+    /// Dev-only escape hatch (like ContentView's `PUNKTFUNK_AUTOCONNECT`): pretend a controller is
+    /// attached so the gamepad UI can be exercised/screenshotted without physical hardware —
+    /// essential on a headless CI Mac and for `swift run` UI work. Never set in production.
+    private static let forced =
+        ProcessInfo.processInfo.environment["PUNKTFUNK_FORCE_GAMEPAD_UI"] == "1"
+}