PR Summary

• Generate framework-dependent Azure Linux RPMs for both Azure Linux 3 (.cm) and Azure Linux 4 (.azl4) on x86_64 and aarch64.
• Emit Azure Linux 4 RPM metadata with Release: 1.azl4 and select the exact NEVRA produced by rpmbuild.
• Apply the current master/.NET 11 Azure Linux dependency contract to both cm and azl4, including dotnet-runtime-11.0 only for framework-dependent builds.
• Replace the legacy Azure Linux 4 beta PMC mappings with explicit preview and stable mappings for both architectures while retaining the Azure Linux 3 mappings.
• Accept .azl4 in both RPM filename validators, with literal dots escaped and filenames anchored.

PR Context

This is the post-release master follow-up to the v7.7.0-preview.5 merge-back in #28090. The release tag and release branch remain unchanged.

The PMC logical prefixes follow the existing mapping convention for the public feeds at /azurelinux/4/{preview|prod}/microsoft/{arch}; Run.ps1 appends -yum when resolving the PMC repository. Channel-specific mappings prevent preview packages from reaching stable repositories and vice versa.

Validation

• Pester 5.6.1: 32 targeted packaging and Linux package-name tests passed.
• Covered .azl4 filenames for x86_64 and aarch64, Release: 1.azl4, Azure Linux dependency selection, all four PMC mappings and channel policy, retained .cm mappings, and malformed filename rejection.
• Parsed all changed PowerShell files and mapping.json; git diff --check passed.
• Confirmed the four requested public Azure Linux 4 feed paths are available on packages.microsoft.com and expose native .azl4 RPM content.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge.
• Breaking changes
  • None
• User-facing changes
  • Not Applicable
• Testing - New and feature
  • Added targeted tests