eng/scripts/get-aspire-cli.ps1: Shared block of code

- Group shared helper functions into a clearly marked shared block
- No behavior changes; function signatures preserved
- Align help text default path with ~/.aspire

Author: radical

eng/scripts/get-aspire-cli.ps1

@@ -17,7 +17,7 @@
     Pass a specific version to get CLI for that version.
 
 .PARAMETER InstallPath
-    Directory to install the CLI (default: %USERPROFILE%\.aspire\bin on Windows, `$HOME/.aspire/bin on Unix)
+    Directory to install the CLI (default: %USERPROFILE%\.aspire on Windows, `$HOME/.aspire on Unix)
 
 .PARAMETER Version
     Version of the Aspire CLI to download (default: unset)
@@ -136,6 +136,10 @@ if ($PSVersionTable.PSVersion.Major -lt $Script:Config.MinimumPowerShellVersion)
     }
 }
 
+# =====================
+# Shared helpers block
+# =====================
+
 # Consolidated output function with fallback for platforms that don't support Write-Host
 function Write-Message {
     [CmdletBinding()]
@@ -558,6 +562,10 @@ function Invoke-SecureWebRequest {
     }
 }
 
+# ==========================
+# End shared helpers block
+# ==========================
+
 # Enhanced file download wrapper with validation
 function Invoke-FileDownload {
     [CmdletBinding()]