Add README.md for the Aspire.Hosting.Azure.AppService package

[ShilpiRach]

Description

Adds README.md for the Aspire.Hosting.Azure.AppService package.

Fixes # (issue)

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Link to aspire-docs issue (consider using one of the following templates):
      • New (or update) doc-idea template
      • New breaking-change template
      • New diagnostic template
  • No

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 12528

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 12528"

[Copilot]

Pull Request Overview

This PR adds a comprehensive README for the Aspire.Hosting.Azure.AppService library, documenting how to configure and deploy .NET Aspire applications to Azure App Service. The documentation covers prerequisites, installation, usage examples, constraints, and customization options.

Key Changes

• New README file providing complete documentation for the Azure App Service hosting integration
• Includes usage examples for App Service Environment setup and project publishing
• Documents constraints, customization options, and Azure integration patterns

[davidfowl]

/backport to release/13.0

[github-actions]

Started backporting to release/13.0: https://github.com/dotnet/aspire/actions/runs/18961911259