refactor(windows scripts): remove BOM and improve UTF-8 handling

windows/apps/containers.ps1

@@ -1,4 +1,4 @@
-<#
+<#
     LXS - Containers and virtualization (Windows)
     Description: WSL 2, Hyper-V, Docker Desktop and VirtualBox.
     Repo: https://git.hyko.cx/hykocx/lxs
@@ -19,7 +19,10 @@ if ($LxsLibPath -and (Test-Path $LxsLibPath)) {
         Write-Error 'Failed to fetch lib/common.ps1'
         exit 1
     }
-    . ([scriptblock]::Create($LxsLibSource))
+    # The library ships with a UTF-8 BOM (Windows PowerShell 5.1 needs it to
+    # read the file as UTF-8); over HTTP that BOM arrives as a leading U+FEFF
+    # character, which the parser will not accept.
+    . ([scriptblock]::Create(($LxsLibSource -replace '^\uFEFF', '')))
 }
 
 $env:LXS_LOG_FILE = Join-Path (Get-LxsTempDir) 'lxs_containers.log'
@@ -86,7 +89,7 @@ function Install-LxsWsl {
     Write-Host ''
     & wsl.exe --install
     if ($LASTEXITCODE -eq 0) {
-        Write-LxsOk 'WSL install started — reboot to finish'
+        Write-LxsOk 'WSL install started - reboot to finish'
     } else {
         Write-LxsWarn "wsl --install exited with code $LASTEXITCODE"
     }
@@ -110,7 +113,7 @@ function Enable-LxsHyperV {
     Write-Host ''
     try {
         Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All -All -NoRestart -ErrorAction Stop | Out-Null
-        Write-LxsOk 'Hyper-V enabled — reboot to finish'
+        Write-LxsOk 'Hyper-V enabled - reboot to finish'
     } catch {
         Write-LxsErr "Could not enable Hyper-V: $($_.Exception.Message)"
     }