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/PunktfunkClient/Home/LibraryWidgets.swift

@@ -0,0 +1,95 @@
+// Reusable library widgets, shared by the touch grid (LibraryView's `GameCard`) and the gamepad
+// coverflow (LibraryCoverflowView's cover cell).
+
+import PunktfunkKit
+import SwiftUI
+#if canImport(UIKit)
+import UIKit
+#elseif canImport(AppKit)
+import AppKit
+#endif
+
+/// The store-provenance badge (Steam vs. a user-curated custom entry) overlaid on a poster —
+/// shared by the touch grid's `GameCard` and the gamepad coverflow's cover cell.
+struct StoreBadge: View {
+    let isCustom: Bool
+
+    var body: some View {
+        Text(isCustom ? "Custom" : "Steam")
+            .font(.geist(11, .semibold, relativeTo: .caption2))
+            .padding(.horizontal, 6)
+            .padding(.vertical, 3)
+            .background(.ultraThinMaterial, in: Capsule())
+            .padding(6)
+    }
+}
+
+#if canImport(UIKit)
+private typealias PlatformImage = UIImage
+#elseif canImport(AppKit)
+private typealias PlatformImage = NSImage
+#endif
+
+private extension Image {
+    init(platformImage: PlatformImage) {
+        #if canImport(UIKit)
+        self.init(uiImage: platformImage)
+        #elseif canImport(AppKit)
+        self.init(nsImage: platformImage)
+        #endif
+    }
+}
+
+/// Sequentially tries cover-art URLs over `session` (so a paired client can reach the host's own
+/// art proxy, not just public CDNs — see `LibraryImageLoader`), advancing past any that fail to
+/// load, then a placeholder. The loaded image is hard-clipped to fill the card's actual frame
+/// regardless of its own aspect ratio: a portrait capsule fills it as intended, but a fallback
+/// banner (wide hero/header art, used when a title has no portrait capsule) would otherwise report
+/// a much wider intrinsic size than the card and overflow into neighboring cards. Not `private` —
+/// the gamepad coverflow (`LibraryCoverflowView`) reuses it directly rather than re-fetching art.
+struct PosterImage: View {
+    let candidates: [URL]
+    let title: String
+    let session: URLSession?
+    @State private var index = 0
+    @State private var image: PlatformImage?
+
+    var body: some View {
+        Group {
+            if let image {
+                Image(platformImage: image)
+                    .resizable()
+                    .scaledToFill()
+            } else if index < candidates.count {
+                ZStack { placeholder; ProgressView() }
+            } else {
+                placeholder
+            }
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .clipped()
+        .task(id: index) { await loadCurrent() }
+    }
+
+    private func loadCurrent() async {
+        guard index < candidates.count else { return }
+        guard let session, let data = try? await session.data(from: candidates[index]).0,
+              let loaded = PlatformImage(data: data)
+        else {
+            index += 1 // advance to the next candidate (or past the end → placeholder)
+            return
+        }
+        image = loaded
+    }
+
+    private var placeholder: some View {
+        ZStack {
+            Rectangle().fill(.quaternary)
+            Text(title)
+                .font(.geist(17, .semibold, relativeTo: .headline))
+                .multilineTextAlignment(.center)
+                .foregroundStyle(.secondary)
+                .padding(8)
+        }
+    }
+}