[Feature]: Add Az.PrivateTrafficManager module for Private Traffic Manager service

### Description of the new feature

## Summary

Requesting the onboarding of a new `Az.PrivateTrafficManager` PowerShell module for the Private Traffic Manager (PTM) service under Microsoft.Network.

PR: https://github.com/Azure/azure-powershell/pull/29729

## Details

- **Resource Provider**: Microsoft.Network/PrivateTrafficManager
- **API Version**: `2026-02-09-preview`
- **ARM Spec PR**: [Azure/azure-rest-api-specs-pr#26898](https://github.com/Azure/azure-rest-api-specs-pr/pull/26898)
- **Release Plan**: ADO task #32848
- **Target Release**: Engineering build (for internal/private distribution)

## Cmdlets Requested (20 total)

| Resource | Cmdlets |
|----------|---------|
| Profile | `New/Get/Update/Remove-AzPrivateTrafficManagerProfile` |
| Endpoint | `New/Get/Update/Remove-AzPrivateTrafficManagerEndpoint` |
| HealthPolicy | `New/Get/Update/Remove-AzPrivateTrafficManagerHealthPolicy` |
| TopologyMap | `New/Get/Update/Remove-AzPrivateTrafficManagerTopologyMap` |
| Site | `New/Get/Update/Remove-AzPrivateTrafficManagerSite` |

## Context

Private Traffic Manager is a new Azure networking service that provides private DNS-based traffic management. The module is AutoRest-generated from a TypeSpec-based ARM specification. Implementation PR is ready for review.

### Proposed implementation details (optional)

- Module type: AutoRest-generated (TypeSpec spec)
- Generated using AutoRest PowerShell v4.x
- Polymorphism directive applied for ProbeHealthPolicy
- Set-* cmdlets removed per ARM best practices
- Tests: 118 parameter-set validation tests passing
- PR: [azure-powershell PR link once created]

Start with implementation PR 29729 and the AutoRest-generated Az.PrivateTrafficManager module described in the issue. Review the 118 parameter-set validation tests and the five requested resource groups; done means the module and all 20 requested cmdlets pass validation and are ready for the target engineering build.

Written by the indexing model from the issue text.