refactor(input): own pointer and callback lifetime

Move camera pointer, framebuffer resize, and retained/devtools input edges behind focused reversible owners. Preserve input priority while making shutdown deactivate callbacks before live-session retirement and retry physical detach without stranding transport teardown.

tests/AcDream.App.Tests/Input/DispatcherCameraInputSourceTests.cs

@@ -0,0 +1,53 @@
+using AcDream.App.Input;
+using AcDream.UI.Abstractions.Input;
+using Silk.NET.Input;
+
+namespace AcDream.App.Tests.Input;
+
+public sealed class DispatcherCameraInputSourceTests
+{
+    [Fact]
+    public void ExactUnbindRestoresNeutralCameraSampling()
+    {
+        var keyboard = new Keyboard();
+        var mouse = new Mouse();
+        var dispatcher = InputDispatcher.CreateDetached(keyboard, mouse, new KeyBindings());
+        dispatcher.Attach();
+        var other = InputDispatcher.CreateDetached(new Keyboard(), new Mouse(), new KeyBindings());
+        other.Attach();
+        var source = new DispatcherCameraInputSource();
+        source.Bind(dispatcher);
+        dispatcher.TrySetAutomationActionHeld(InputAction.MovementForward, held: true);
+
+        source.Unbind(other);
+        Assert.True(source.CaptureFly().Forward);
+        source.Unbind(dispatcher);
+
+        Assert.False(source.IsAvailable);
+        Assert.Equal(default, source.CaptureFly());
+        Assert.Equal(default, source.CaptureChaseAdjustment());
+    }
+
+    private sealed class Keyboard : IKeyboardSource
+    {
+#pragma warning disable CS0067
+        public event Action<Key, ModifierMask>? KeyDown;
+        public event Action<Key, ModifierMask>? KeyUp;
+#pragma warning restore CS0067
+        public bool IsHeld(Key key) => false;
+        public ModifierMask CurrentModifiers => ModifierMask.None;
+    }
+
+    private sealed class Mouse : IMouseSource
+    {
+#pragma warning disable CS0067
+        public event Action<MouseButton, ModifierMask>? MouseDown;
+        public event Action<MouseButton, ModifierMask>? MouseUp;
+        public event Action<float, float>? MouseMove;
+        public event Action<float>? Scroll;
+#pragma warning restore CS0067
+        public bool IsHeld(MouseButton button) => false;
+        public bool WantCaptureMouse => false;
+        public bool WantCaptureKeyboard => false;
+    }
+}