chore: remove NoWarn and fix .NET 10 build warnings across platforms (#9301)

* deps: bump ZXing.Net.Bindings.SkiaSharp from 0.16.14 to 0.16.22

Patch update to the latest stable release on the 0.16.x line. No breaking changes, no public API changes - purely internal fixes.

Verified by a full Release build of v2rayN.sln on .NET 10; no new warnings or errors are introduced.

* chore: remove NoWarn and fix .NET 10 build warnings

Removes the repository-level NoWarn suppression from Directory.Build.props and addresses the warnings that surface on top of the .NET 10 migration in #9179, keeping Debug, Release, and cross-platform publishes warning-free without suppressing warnings globally.

Changes:

- Removes <NoWarn>CA1031;CS1591;NU1507;CA1416;IDE0058;IDE0053;IDE0200</NoWarn> from Directory.Build.props.

- Annotates Windows-only APIs with [SupportedOSPlatform] and [SupportedOSPlatformGuard] so CA1416 accepts that the Windows surface is gated behind Utils.IsWindows() / Utils.IsNonWindows().

- Splits Utils.SetUnixFileMode into a cross-platform wrapper and a private [UnsupportedOSPlatform("windows")] implementation so File.SetUnixFileMode never reaches the analyzer on Windows builds.

- Adds a parameterless constructor to MessageBoxDialog so Avalonia's runtime XAML loader (AVLN3001) can instantiate the dialog.

- Moves the WPF high-DPI configuration from app.manifest to <ApplicationHighDpiMode>PerMonitorV2</ApplicationHighDpiMode> in v2rayN.csproj, fixing WFO0003.

- Adds global using System.Runtime.Versioning; to ServiceLib and v2rayN.Desktop so the platform attributes are usable project-wide.

* test: make cycle dependency tests locale-independent

Accept the localized Russian cycle dependency diagnostic in CoreConfigContextBuilderTests so the assertions pass when tests run under a Russian UI culture.

* fix: tighten Unix platform handling

Adds Linux and macOS platform guards so the analyzer can narrow calls through Utils.IsLinux() and Utils.IsMacOS().

Marks the Linux/macOS autostart and system proxy helpers with explicit platform attributes.

Updates Utils.GetSystemHosts() to read /etc/hosts on Linux and macOS while keeping the existing Windows hosts and hosts.ics merge behavior.

v2rayN/ServiceLib/Common/Utils.cs

@@ -864,15 +864,25 @@ public class Utils
 
     public static Dictionary<string, string> GetSystemHosts()
     {
-        var hosts = GetSystemHosts(@"C:\Windows\System32\drivers\etc\hosts");
-        var hostsIcs = GetSystemHosts(@"C:\Windows\System32\drivers\etc\hosts.ics");
-
-        foreach (var (key, value) in hostsIcs)
+        if (IsWindows())
         {
-            hosts[key] = value;
+            var hosts = GetSystemHosts(@"C:\Windows\System32\drivers\etc\hosts");
+            var hostsIcs = GetSystemHosts(@"C:\Windows\System32\drivers\etc\hosts.ics");
+
+            foreach (var (key, value) in hostsIcs)
+            {
+                hosts[key] = value;
+            }
+
+            return hosts;
         }
 
-        return hosts;
+        if (IsLinux() || IsMacOS())
+        {
+            return GetSystemHosts("/etc/hosts");
+        }
+
+        return new Dictionary<string, string>();
     }
 
     public static async Task<string?> GetCliWrapOutput(string filePath, string? arg)
@@ -1114,12 +1124,16 @@ public class Utils
 
     #region Platform
 
+    [SupportedOSPlatformGuard("windows")]
     public static bool IsWindows() => OperatingSystem.IsWindows();
 
+    [SupportedOSPlatformGuard("linux")]
     public static bool IsLinux() => OperatingSystem.IsLinux();
 
+    [SupportedOSPlatformGuard("macos")]
     public static bool IsMacOS() => OperatingSystem.IsMacOS();
 
+    [UnsupportedOSPlatformGuard("windows")]
     public static bool IsNonWindows() => !OperatingSystem.IsWindows();
 
     public static string GetExeName(string name)
@@ -1214,6 +1228,16 @@ public class Utils
     }
 
     public static bool SetUnixFileMode(string? fileName)
+    {
+        if (IsWindows())
+        {
+            return false;
+        }
+        return SetUnixFileModeInternal(fileName);
+    }
+
+    [UnsupportedOSPlatform("windows")]
+    private static bool SetUnixFileModeInternal(string? fileName)
     {
         try
         {