lang: detect forced UTF-8 ACP, try to opt-out (#853)

## Link to GitHub Issue or related Pull Request, if one exists
n/a

## Description of change

Fixes broken Japanese text when Windows `Use Unicode UTF-8 for worldwide
language support` setting is enabled. This setting changes the system
ACP to UTF-8 (65001), causing legacy Shift-JIS lead-byte checks to fail.

Windows 11: requests the legacy process code page through the manifest.

Windows 10: detects ACP 65001 (UTF-8), warns the user via deferred log,
and applies compatibility hook (only for popn pika model for now)

Windows 7 and below - UTF-8 option doesn't exist.

## Testing

src/spice2x/build/manifest.manifest

@@ -6,6 +6,7 @@
         <asmv3:windowsSettings xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">
             <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2</dpiAwareness>
             <dpiAware>true</dpiAware>
+            <activeCodePage xmlns="http://schemas.microsoft.com/SMI/2019/WindowsSettings">Legacy</activeCodePage>
         </asmv3:windowsSettings>
     </asmv3:application>
     <dependency>