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

windows/tools/restore-point.ps1

@@ -1,4 +1,4 @@
-<#
+<#
     LXS - System Restore Point (Windows)
     Description: Enable System Protection, create checkpoints, list them and
                  roll back. The safety net for harden.ps1 and debloat.ps1.
@@ -20,7 +20,10 @@ 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_restore_point.log'
@@ -70,7 +73,7 @@ function Show-LxsProtectionStatus {
                 Write-Host "  Shadow storage: $usedGB GB used of $maxGB GB allocated"
             }
         } else {
-            Write-LxsWarn "System Protection looks OFF for $drive — no restore points can be created."
+            Write-LxsWarn "System Protection looks OFF for $drive - no restore points can be created."
         }
     } catch {
         Write-LxsWarn 'Could not read the shadow storage configuration.'