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

windows/lxs.ps1

@@ -1,4 +1,4 @@
-<#
+<#
     LXS - Windows multi-tool
     Description: Centralized workstation management and deployment toolkit
     Repo: https://git.hyko.cx/hykocx/lxs
@@ -73,7 +73,10 @@ if ($libPath -and (Test-Path $libPath)) {
         Write-Error 'Failed to fetch lib/common.ps1'
         exit 1
     }
-    . ([scriptblock]::Create($libSource))
+    # Strip the UTF-8 BOM: it is required in the file (Windows PowerShell 5.1
+    # reads a BOM-less .ps1 with the ANSI codepage) but arrives as a leading
+    # U+FEFF character when fetched over HTTP, which the parser rejects.
+    . ([scriptblock]::Create(($libSource -replace '^\uFEFF', '')))
 }
 
 # ═══════════════════════════════════════════════════════════════════════════
@@ -113,7 +116,7 @@ function Test-LxsRemoteVersion {
     }
 
     if ($age -ge $LxsVersionTtl) {
-        # Refresh inline but on a short leash — a slow repo must not stall the menu.
+        # Refresh inline but on a short leash - a slow repo must not stall the menu.
         try {
             $remote = Invoke-RestMethod -Uri "$LxsRawBase/VERSION" -TimeoutSec 3 `
                 -Headers @{ 'Cache-Control' = 'no-cache' } -UseBasicParsing -ErrorAction Stop
@@ -162,7 +165,7 @@ function Show-LxsHeader {
         $totalMem = [math]::Round($os.TotalVisibleMemorySize / 1MB, 1)
         $usedMem = [math]::Round(($os.TotalVisibleMemorySize - $os.FreePhysicalMemory) / 1MB, 1)
     } catch {
-        # CIM unavailable — the header degrades but the menu still works.
+        # CIM unavailable - the header degrades but the menu still works.
     }
 
     $cores = $env:NUMBER_OF_PROCESSORS
@@ -318,7 +321,7 @@ function Invoke-LxsCmdTool {
 }
 
 # ═══════════════════════════════════════════════════════════════════════════
-# setup / update — download the repo zip and mirror it into $LxsInstallDir.
+# setup / update - download the repo zip and mirror it into $LxsInstallDir.
 # Everything lands under %LOCALAPPDATA%, so no elevation is needed here;
 # individual tools elevate themselves when they touch the machine.
 # ═══════════════════════════════════════════════════════════════════════════