feat(toolkit): complete macOS Intune Toolkit v1

Core enhancements:
- Expanded default export/import scope to ~45 object types including DeviceManagementIntents
- Added -AllPages pagination support across Graph queries for large tenants
- Invoke-GraphRequest now throws on 4xx/5xx instead of silently returning null
- Added macOS Keychain fallback for secret retrieval in headless auth flow
- Added NameSearchPattern/NameReplacePattern mutation support through export/import forms

New toolkit scripts:
- Bulk-AppAssignment.ps1: bulk-assign apps to groups/All Users/All Devices
- Bulk-AssignmentManager.ps1: add/remove assignments for any policy type with correct @odata.type
- Backup-Restore-Assignments.ps1: JSON backup with cross-tenant group resolution
- Export-AssignmentsToCsv.ps1: CSV/Markdown documentation output
- Bulk-RenamePolicies.ps1: regex search/replace and prefix mutations
- Bulk-DeviceOperations.ps1: delete/retire/wipe/lock/sync with -WhatIf safeguards
- Start-IntuneManagementTui.ps1: interactive terminal UI for headless operations
- Create-IntuneManagementApp.ps1: helper for app registration setup

Updated existing scripts:
- Export-Policies.ps1 / Import-Policies.ps1: wired mutation params through
- Start-HeadlessIntune.ps1: integrated TUI and new parameter forwarding

Core.psm1

@@ -6,6 +6,13 @@ Headless runtime helpers for macOS Intune Management.
 This module provides the non-UI runtime used by the CLI entrypoints.
 #>
 
+# Microsoft.Graph.Authentication registers an alias Invoke-GraphRequest -> Invoke-MgGraphRequest.
+# Remove it so our local function in MSGraph.psm1 is used instead.
+if (Get-Alias Invoke-GraphRequest -ErrorAction SilentlyContinue)
+{
+    Remove-Item Alias:\Invoke-GraphRequest -Force -ErrorAction SilentlyContinue
+}
+
 function Get-ModuleVersion
 {
     '4.0.0'
@@ -20,6 +27,42 @@ function Invoke-AppDoEvents
 {
 }
 
+function Expand-FileName
+{
+    param([string]$Path)
+    if(-not $Path) { return $Path }
+    $expanded = [Environment]::ExpandEnvironmentVariables($Path)
+    if($expanded -like "~/*" -or $expanded -eq "~")
+    {
+        $expanded = $expanded -replace "^~", $HOME
+    }
+    return $expanded
+}
+
+function Remove-InvalidFileNameChars
+{
+    param([string]$Name)
+    if([string]::IsNullOrEmpty($Name)) { return $Name }
+    $invalid = [IO.Path]::GetInvalidFileNameChars()
+    foreach($char in $invalid)
+    {
+        $Name = $Name.Replace($char, '_')
+    }
+    # Also replace path separator if present (relevant on Unix)
+    $Name = $Name.Replace('/', '_')
+    $Name
+}
+
+function Remove-Property
+{
+    param($Object, [string]$PropertyName)
+    if(-not $Object -or [string]::IsNullOrEmpty($PropertyName)) { return }
+    if($Object.PSObject.Properties[$PropertyName])
+    {
+        $Object.PSObject.Properties.Remove($PropertyName)
+    }
+}
+
 function Start-CoreApp
 {
     param($View)
@@ -388,25 +431,44 @@ function New-HeadlessControl
         [string]$Type = "TextBox"
     )
 
-    [PSCustomObject]@{
+    $control = [PSCustomObject]@{
         Name = $Name
         Type = $Type
         Focusable = ($Type -ne "DataGrid")
         Visibility = "Visible"
         IsEnabled = $true
-        Text = ""
-        IsChecked = $false
-        SelectedValue = $null
-        SelectedIndex = -1
-        SelectedItem = $null
-        SelectedItems = @()
-        ItemsSource = @()
-        Items = @()
-        Columns = @()
-        Content = ""
         Parent = $null
         DataContext = $null
     }
+
+    switch($Type)
+    {
+        "TextBox" {
+            $control | Add-Member -NotePropertyName Text -NotePropertyValue ""
+        }
+        "CheckBox" {
+            $control | Add-Member -NotePropertyName IsChecked -NotePropertyValue $false
+        }
+        "ComboBox" {
+            $control | Add-Member -NotePropertyName SelectedValue -NotePropertyValue $null
+            $control | Add-Member -NotePropertyName SelectedIndex -NotePropertyValue -1
+            $control | Add-Member -NotePropertyName SelectedItem -NotePropertyValue $null
+            $control | Add-Member -NotePropertyName SelectedItems -NotePropertyValue @()
+            $control | Add-Member -NotePropertyName ItemsSource -NotePropertyValue @()
+            $control | Add-Member -NotePropertyName Items -NotePropertyValue @()
+        }
+        "Label" {
+            $control | Add-Member -NotePropertyName Content -NotePropertyValue ""
+        }
+        "DataGrid" {
+            $control | Add-Member -NotePropertyName ItemsSource -NotePropertyValue @()
+            $control | Add-Member -NotePropertyName Columns -NotePropertyValue @()
+            $control | Add-Member -NotePropertyName SelectedItems -NotePropertyValue @()
+            $control | Add-Member -NotePropertyName SelectedItem -NotePropertyValue $null
+        }
+    }
+
+    $control
 }
 
 function New-HeadlessForm