fix: remove BOM/SIG from *.rc files

Build/scripts/rc_to_utf8.ps1

@@ -0,0 +1,34 @@
+# Convert UTF-8-BOM encoded language RC files to pure UTF-8 (no BOM)
+# Usage: .\rc_to_utf8.ps1
+
+$ErrorActionPreference = "Stop"
+$ScriptDir  = Split-Path -Parent $MyInvocation.MyCommand.Path
+$RepoRoot   = Split-Path -Parent (Split-Path -Parent $ScriptDir)
+$LangDir    = Join-Path $RepoRoot "language"
+
+Write-Host "Stripping UTF-8 BOM from RC files in: $LangDir" -ForegroundColor Yellow
+
+$bom       = [byte[]](0xEF, 0xBB, 0xBF)
+$converted = 0
+$skipped   = 0
+
+Get-ChildItem -Path $LangDir -Filter "*.rc" -Recurse | ForEach-Object {
+    $bytes = [System.IO.File]::ReadAllBytes($_.FullName)
+    if ($bytes.Length -ge 3 -and $bytes[0] -eq $bom[0] -and $bytes[1] -eq $bom[1] -and $bytes[2] -eq $bom[2]) {
+        $stripped = $bytes[3..($bytes.Length - 1)]
+        [System.IO.File]::WriteAllBytes($_.FullName, $stripped)
+        Write-Host "  Converted: $($_.FullName.Substring($LangDir.Length + 1))" -ForegroundColor Cyan
+        $converted++
+    }
+    else {
+        $skipped++
+    }
+}
+
+Write-Host ""
+if ($converted -gt 0) {
+    Write-Host "Done! Converted $converted file(s), skipped $skipped file(s) (no BOM)." -ForegroundColor Green
+}
+else {
+    Write-Host "Done! No files needed conversion ($skipped file(s) already BOM-free)." -ForegroundColor Green
+}