Add strict YAML file imports

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: MariusStorhaug

src/functions/private/Get-YamlTextEncoding.ps1

@@ -0,0 +1,57 @@
+function Get-YamlTextEncoding {
+    <#
+        .SYNOPSIS
+        Creates a strict text encoding for YAML file input or output.
+
+        .DESCRIPTION
+        Returns an encoding that throws when bytes or characters cannot be
+        represented. The encoding preamble matches the public encoding name.
+
+        .PARAMETER Name
+        The public YAML file encoding name.
+
+        .EXAMPLE
+        Get-YamlTextEncoding -Name utf8
+
+        Returns strict UTF-8 without a byte order mark.
+
+        .INPUTS
+        None.
+
+        .OUTPUTS
+        System.Text.Encoding
+    #>
+    [OutputType(
+        [System.Text.UTF8Encoding],
+        [System.Text.UnicodeEncoding],
+        [System.Text.UTF32Encoding]
+    )]
+    [CmdletBinding()]
+    param (
+        # Selects the strict decoder and its output preamble policy.
+        [Parameter(Mandatory)]
+        [ValidateSet('utf8', 'utf8BOM', 'utf16LE', 'utf16BE', 'utf32LE', 'utf32BE')]
+        [string] $Name
+    )
+
+    switch ($Name) {
+        'utf8' {
+            [System.Text.UTF8Encoding]::new($false, $true)
+        }
+        'utf8BOM' {
+            [System.Text.UTF8Encoding]::new($true, $true)
+        }
+        'utf16LE' {
+            [System.Text.UnicodeEncoding]::new($false, $true, $true)
+        }
+        'utf16BE' {
+            [System.Text.UnicodeEncoding]::new($true, $true, $true)
+        }
+        'utf32LE' {
+            [System.Text.UTF32Encoding]::new($false, $true, $true)
+        }
+        'utf32BE' {
+            [System.Text.UTF32Encoding]::new($true, $true, $true)
+        }
+    }
+}