Add Azure auth sample app

[paulmedynski]

Description

Adds a sample app for testing Azure authentication with flexibility to supply published and local SqlClient packages.

[Copilot]

Pull request overview

This PR adds a new sample console application for testing Azure authentication with Microsoft.Data.SqlClient. The app is designed as a smoke test to verify package compatibility and Azure AD authentication functionality, with support for testing against both published NuGet packages and locally-built packages from the packages/ directory.

Changes:

• Adds AzureAuthentication sample app in doc/apps/AzureAuthentication/ with flexible package version configuration
• Includes comprehensive documentation with usage examples and build instructions
• Updates doc/Directory.Packages.props to reference the latest stable SqlClient version (6.1.4)

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/Microsoft.Data.SqlClient.sln	Adds the new AzureAuthentication project to the solution
doc/apps/AzureAuthentication/AzureAuthentication.csproj	Project file targeting net481 and net10.0 with conditional Azure package references
doc/apps/AzureAuthentication/Program.cs	Main application implementing command-line interface with connection testing and event logging
doc/apps/AzureAuthentication/README.md	Comprehensive documentation covering purpose, usage, examples, and prerequisites
doc/apps/AzureAuthentication/Directory.Build.props	Enables Central Package Management for the sample app
doc/apps/AzureAuthentication/Directory.Packages.props	Defines default package versions with overridable MSBuild properties
doc/apps/AzureAuthentication/NuGet.config	Configures local packages/ directory as a package source
doc/apps/AzureAuthentication/GeneratePackageVersions.targets	MSBuild task to generate code exposing package versions at runtime
doc/apps/AzureAuthentication/packages/.gitkeep	Ensures git tracks the empty packages directory
doc/Directory.Packages.props	Updates SqlClient reference to latest stable version 6.1.4

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.97%. Comparing base (326a242) to head (d8fbc3d).
⚠️ Report is 4 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (326a242) and HEAD (d8fbc3d). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (326a242)	HEAD (d8fbc3d)
CI-SqlClient	1	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3988      +/-   ##
==========================================
- Coverage   72.65%   64.97%   -7.68%     
==========================================
  Files         287      282       -5     
  Lines       43134    66043   +22909     
==========================================
+ Hits        31337    42913   +11576     
- Misses      11797    23130   +11333     

Flag	Coverage Δ
CI-SqlClient	?
PR-SqlClient-Project	64.97% <ø> (?)

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[mdaigle]

Looks complete. Is your goal to give an example for users? or is this intended as an easy way to manually test the full stack?

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 7 comments.

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[paulmedynski]

@copilot open a new pull request to apply changes based on the comments in this thread. Do not consider outdated comments.

[Copilot]

@paulmedynski I've opened a new pull request, #4027, to work on those changes. Once the pull request is ready, I'll request review from you.

[cheenamalhotra]

Let's do more samples changes in the future, not a blocker to get this checked in, but we should aim to consolidate both doc\samples and doc\app project build experiences.