Add PSGet to PSResourceGet migration tool

Adds a PowerShell-based migration tool that scans .ps1/.psm1/.psd1 files
for PowerShellGet v2 cmdlet usage and converts them to PSResourceGet
equivalents using AST-based parsing.

Features:
- 25 cmdlet mappings (Find-Module → Find-PSResource, etc.)
- Parameter transformations (version ranges, renames, removals)
- Dry-run report mode and in-place apply with backups
- 30 Pester tests covering all conversion scenarios

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

Author: adityapatwardhan

tool/migration/ConvertTo-PSResourceGet.ps1

@@ -0,0 +1,101 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+
+<#
+.SYNOPSIS
+    Converts PowerShellGet v2 cmdlet usage to PSResourceGet equivalents.
+
+.DESCRIPTION
+    Scans PowerShell files (.ps1, .psm1, .psd1) for PSGet v2 cmdlet usage
+    (e.g., Install-Module, Find-Module) and converts them to their
+    PSResourceGet equivalents (e.g., Install-PSResource, Find-PSResource).
+
+    By default, runs in WhatIf/report mode. Use -Apply to modify files.
+
+.PARAMETER Path
+    Path to a file or directory to scan. Supports wildcards.
+    Defaults to the current directory.
+
+.PARAMETER Recurse
+    When Path is a directory, scan subdirectories recursively.
+
+.PARAMETER Apply
+    Apply the changes to files in-place. Without this switch, only a report is generated.
+
+.PARAMETER BackupPath
+    Directory for backup copies. Defaults to .bak files alongside originals.
+
+.PARAMETER PassThru
+    Emit structured result objects to the pipeline instead of formatted output.
+
+.EXAMPLE
+    # Dry-run: scan current directory recursively and show migration report
+    .\ConvertTo-PSResourceGet.ps1 -Path . -Recurse
+
+.EXAMPLE
+    # Apply changes with backups
+    .\ConvertTo-PSResourceGet.ps1 -Path .\scripts -Recurse -Apply -BackupPath .\backups
+
+.EXAMPLE
+    # Scan a single file and get structured output
+    .\ConvertTo-PSResourceGet.ps1 -Path .\deploy.ps1 -PassThru
+#>
+
+[CmdletBinding(SupportsShouldProcess)]
+param(
+    [Parameter(Position = 0)]
+    [string] $Path = '.',
+
+    [switch] $Recurse,
+
+    [switch] $Apply,
+
+    [string] $BackupPath,
+
+    [switch] $PassThru
+)
+
+# Import the migration module
+$modulePath = Join-Path $PSScriptRoot 'PSGetMigration.psm1'
+Import-Module $modulePath -Force
+
+# Resolve files to scan
+$resolvedPath = Resolve-Path -Path $Path -ErrorAction Stop
+
+$filesToScan = if (Test-Path $resolvedPath.Path -PathType Container) {
+    $gciParams = @{
+        Path    = $resolvedPath.Path
+        Include = @('*.ps1', '*.psm1', '*.psd1')
+        File    = $true
+    }
+    if ($Recurse) {
+        $gciParams['Recurse'] = $true
+    }
+    Get-ChildItem @gciParams
+}
+else {
+    Get-Item $resolvedPath.Path
+}
+
+if (-not $filesToScan) {
+    Write-Host "No PowerShell files found at '$Path'." -ForegroundColor Yellow
+    return
+}
+
+Write-Host "Scanning $($filesToScan.Count) file(s)..." -ForegroundColor Cyan
+
+# Process each file
+$convertParams = @{}
+if ($Apply) { $convertParams['Apply'] = $true }
+if ($BackupPath) { $convertParams['BackupPath'] = $BackupPath }
+
+$results = $filesToScan | ForEach-Object {
+    ConvertTo-PSResourceGetScript -Path $_.FullName @convertParams
+}
+
+if ($PassThru) {
+    $results
+}
+else {
+    $results | Format-MigrationReport
+}

tool/migration/PSGetMigration.psd1

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+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+
+@{
+    RootModule        = 'PSGetMigration.psm1'
+    ModuleVersion     = '0.1.0'
+    GUID              = 'a3f7b2c1-4d5e-6f78-9a0b-c1d2e3f4a5b6'
+    Author            = 'Microsoft Corporation'
+    CompanyName       = 'Microsoft Corporation'
+    Copyright         = '(c) Microsoft Corporation. All rights reserved.'
+    Description       = 'Migration tool to convert PowerShellGet v2 (PSGet) cmdlet usage to PSResourceGet equivalents.'
+    PowerShellVersion = '5.1'
+    FunctionsToExport = @(
+        'Get-PSGetCommandMapping',
+        'Get-PSGetParameterMapping',
+        'Find-PSGetCommand',
+        'Convert-PSGetCommand',
+        'ConvertTo-PSResourceGetScript',
+        'Format-MigrationReport'
+    )
+    CmdletsToExport   = @()
+    VariablesToExport  = @()
+    AliasesToExport    = @()
+    PrivateData = @{
+        PSData = @{
+            Tags       = @('Migration', 'PSResourceGet', 'PowerShellGet', 'PSGet')
+            ProjectUri = 'https://github.com/PowerShell/PSResourceGet'
+        }
+    }
+}