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/Connection/InputEvents.swift

@@ -0,0 +1,87 @@
+// Convenience constructors for the wire input events (field semantics match
+// punktfunk_core::input::InputEvent; see punktfunk_core.h).
+
+import Foundation
+import PunktfunkCore
+
+public extension PunktfunkInputEvent {
+    private static func make(
+        _ kind: UInt32, code: UInt32, x: Int32, y: Int32, flags: UInt32 = 0
+    ) -> PunktfunkInputEvent {
+        PunktfunkInputEvent(kind: UInt8(kind), _pad: (0, 0, 0), code: code, x: x, y: y, flags: flags)
+    }
+    static func mouseMove(dx: Int32, dy: Int32) -> PunktfunkInputEvent {
+        make(PUNKTFUNK_INPUT_KIND_MOUSE_MOVE.rawValue, code: 0, x: dx, y: dy)
+    }
+    /// Absolute cursor position in client-surface pixels — the host places its cursor
+    /// there (same letterbox mapping and `flags` surface-dims packing as the touch events).
+    /// Used by the iPad pointer fallback when the scene can't pointer-lock and GCMouse's
+    /// relative deltas aren't available; the surface dimensions must each fit in 16 bits.
+    static func mouseMoveAbs(
+        x: Int32, y: Int32, surfaceWidth: UInt32, surfaceHeight: UInt32
+    ) -> PunktfunkInputEvent {
+        make(
+            PUNKTFUNK_INPUT_KIND_MOUSE_MOVE_ABS.rawValue, code: 0, x: x, y: y,
+            flags: ((surfaceWidth & 0xFFFF) << 16) | (surfaceHeight & 0xFFFF))
+    }
+    /// GameStream button ids: 1=left 2=middle 3=right 4=X1 5=X2 (host maps to evdev BTN_*).
+    static func mouseButton(_ button: UInt32, down: Bool) -> PunktfunkInputEvent {
+        make(
+            (down ? PUNKTFUNK_INPUT_KIND_MOUSE_BUTTON_DOWN : PUNKTFUNK_INPUT_KIND_MOUSE_BUTTON_UP).rawValue,
+            code: button, x: 0, y: 0)
+    }
+    /// `vk` is a Windows virtual-key code (the host's vk_to_evdev table consumes these).
+    static func key(_ vk: UInt32, down: Bool) -> PunktfunkInputEvent {
+        make((down ? PUNKTFUNK_INPUT_KIND_KEY_DOWN : PUNKTFUNK_INPUT_KIND_KEY_UP).rawValue, code: vk, x: 0, y: 0)
+    }
+    /// WHEEL_DELTA(120)-scaled; positive = up (vertical) / right (horizontal) — the
+    /// convention Moonlight/SDL use; the host maps onto the ei/wl axes.
+    static func scroll(_ delta: Int32, horizontal: Bool = false) -> PunktfunkInputEvent {
+        make(PUNKTFUNK_INPUT_KIND_MOUSE_SCROLL.rawValue, code: horizontal ? 1 : 0, x: delta, y: 0)
+    }
+
+    // Gamepad (wire contract in punktfunk_core::input::gamepad): one transition per event,
+    // `pad` = controller index, accumulated host-side into a virtual Xbox 360 or DualSense
+    // pad (the session's negotiated `GamepadType`).
+
+    /// `button` is a GameStream buttonFlags bit (A=0x1000 B=0x2000 X=0x4000 Y=0x8000,
+    /// dpad=0x1/2/4/8, start=0x10 back=0x20 LS=0x40 RS=0x80 LB=0x100 RB=0x200 guide=0x400,
+    /// touchpad click=0x100000 — DualSense sessions only, the xpad has no such button).
+    static func gamepadButton(_ button: UInt32, down: Bool, pad: UInt32 = 0) -> PunktfunkInputEvent {
+        make(
+            PUNKTFUNK_INPUT_KIND_GAMEPAD_BUTTON.rawValue,
+            code: button, x: down ? 1 : 0, y: 0, flags: pad)
+    }
+
+    /// Axis ids: 0=LSX 1=LSY 2=RSX 3=RSY (−32768...32767, XInput convention: +y = UP —
+    /// `GCControllerDirectionPad.yAxis` already matches, no flip), 4=LT 5=RT (0...255).
+    static func gamepadAxis(_ axis: UInt32, value: Int32, pad: UInt32 = 0) -> PunktfunkInputEvent {
+        make(PUNKTFUNK_INPUT_KIND_GAMEPAD_AXIS.rawValue, code: axis, x: value, y: 0, flags: pad)
+    }
+
+    // Touch (host-side: libei ei_touchscreen on the virtual output). `id` distinguishes
+    // fingers and is reusable after touchUp; coordinates are absolute pixels on the
+    // client's touch surface, whose size rides in `flags` so the host can rescale —
+    // the surface dimensions must each fit in 16 bits. Built for the iOS variant
+    // (UITouch → these); nothing on macOS emits them yet.
+
+    static func touchDown(
+        id: UInt32, x: Int32, y: Int32, surfaceWidth: UInt32, surfaceHeight: UInt32
+    ) -> PunktfunkInputEvent {
+        make(
+            PUNKTFUNK_INPUT_KIND_TOUCH_DOWN.rawValue, code: id, x: x, y: y,
+            flags: ((surfaceWidth & 0xFFFF) << 16) | (surfaceHeight & 0xFFFF))
+    }
+
+    static func touchMove(
+        id: UInt32, x: Int32, y: Int32, surfaceWidth: UInt32, surfaceHeight: UInt32
+    ) -> PunktfunkInputEvent {
+        make(
+            PUNKTFUNK_INPUT_KIND_TOUCH_MOVE.rawValue, code: id, x: x, y: y,
+            flags: ((surfaceWidth & 0xFFFF) << 16) | (surfaceHeight & 0xFFFF))
+    }
+
+    static func touchUp(id: UInt32) -> PunktfunkInputEvent {
+        make(PUNKTFUNK_INPUT_KIND_TOUCH_UP.rawValue, code: id, x: 0, y: 0)
+    }
+}