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

windows/tools/index.ps1

@@ -1,4 +1,4 @@
-<#
+<#
     LXS - Tools index (Windows)
     Description: Interactive menu listing the scripts in windows\tools
     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', '')))
 }
 
 function Show-LxsToolsMenu {
@@ -66,7 +69,7 @@ function Show-LxsToolsMenu {
         $code = Invoke-LxsSibling -RelativePath $script -SelfDirectory $PSScriptRoot
 
         # Exit code 75 from a child means it already paused on its own
-        # (its own "Back" or end-of-run prompt) — skip the redundant prompt.
+        # (its own "Back" or end-of-run prompt) - skip the redundant prompt.
         if ($code -ne 75) { Read-LxsEnter }
     }
 }