[*] fix missing '#pragma once' on header files (#4014)

`find src -type f -name '*.h' -not -exec grep -q "#pragma once" {} \; -print`

- ignore qt with header guards already
- smaa too

Signed-off-by: lizzie <lizzie@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4014
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: crueter <crueter@eden-emu.dev>

src/common/container_hash.h

@@ -1,7 +1,12 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: 2005-2014 Daniel James
 // SPDX-FileCopyrightText: 2016 Austin Appleby
 // SPDX-License-Identifier: BSL-1.0
 
+#pragma once
+
 #include <array>
 #include <climits>
 #include <cstdint>