Sdl backend (#670)

* [audio] added sdl audio backend and in-tree atrac9 decoder

* [input] replaced per-platform pad readers with sdl gamepad input

* [video] added sdl window and host display plumbing

* [gui] added host display options and per-game render settings

* [bink] synced host movie playback to the guest audio clock

* [cpu] hooked windows write faults into guest image tracking

* [perf] added guest and render profiling, reserved host cpu lanes

* [kernel] fixed stale pthread mutex handle alias

* [host] wired the sdl session, save-data paths and project references

* [audio] hoisted ajm trace stackalloc out of its loop

* [video] Add guest image sync setting

* [build] Strip native symbols

* reuse

src/SharpEmu.HLE/Host/IHostPcmAudioOutput.cs

@@ -0,0 +1,19 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+namespace SharpEmu.HLE.Host;
+
+/// <summary>
+/// Optional host-audio extension for backends that can accept the guest's
+/// interleaved PCM layout directly and perform device conversion themselves.
+/// </summary>
+public interface IHostPcmAudioOutput : IHostAudioOutput
+{
+    IHostAudioStream OpenPcmStream(uint sampleRate, int channels, HostPcmFormat format);
+}
+
+public enum HostPcmFormat
+{
+    Signed16,
+    Float32,
+}