Add PostAction for dotnet.config

[Youssef1313]

Related to #50054

[Copilot]

Pull Request Overview

This PR adds a new PostAction processor for creating or updating dotnet.config files in template generation scenarios. The feature allows templates to automatically configure dotnet.config settings for specific sections, keys, and values.

Key Changes

• Adds CreateOrUpdateDotnetConfigPostActionProcessor that handles creating new dotnet.config files or updating existing ones
• Implements comprehensive test coverage for various scenarios including missing arguments, file creation, section updates, and no-op cases
• Adds localized error and success messages for the new functionality

Reviewed Changes

Copilot reviewed 18 out of 19 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
CreateOrUpdateDotnetConfigPostActionProcessor.cs	Core implementation of the new post-action processor with config file manipulation logic
CreateOrUpdateDotnetConfigPostActionTests.cs	Comprehensive unit tests covering all processor scenarios
Microsoft.TemplateEngine.Cli.csproj	Added dependency on Microsoft.Extensions.Configuration.Ini package
LocalizableStrings.resx	Added new localizable strings for success/error messages
Components.cs	Registered the new processor in the component collection
Multiple .xlf files	Localization files updated with new translation entries

Files not reviewed (1)

• src/Cli/Microsoft.TemplateEngine.Cli/LocalizableStrings.Designer.cs: Language not supported

[Youssef1313]

@dotnet/templating-engine-maintainers @mariam-abdulla @nohwnd Please review

[Youssef1313]

@dotnet/templating-engine-maintainers Can I please have a review here?

[joeloff]

The linked issue mentions .NET 10, main is currently .NET 11. This would need to be ported for RC2 if it needs to be included in 10.0 I think

[Youssef1313]

@joeloff Yes I'll backport after merge. And for next PRs I'll target release/10.0.1xx right away

[nohwnd]

Suggestion:

Looking at the post action that adds project to solution, there are some more things that will need to happen (probably), adding the guid of the post action to templating schema.

And the tests that actually use the action would also be nice to have here:

https://grep.app/search?f.repo.pattern=dotnet%2F&q=D396686C-DE0E-4DE6-906D-291CD29FC5DE

Maybe if this post action moved to the location of https://github.com/dotnet/sdk/blob/main/src/Cli/dotnet/Commands/New/PostActions/DotnetSlnPostActionProcessor.cs#L24

it would be nice to re-use that infrastructure and do it the same.

[Youssef1313]

@nohwnd I addressed your feedback on adding more tests, and opened a doc update on dotnet/templating dotnet/templating#9274. For reusing logic from DotnetSlnPostActionPreprocessor, my logic here is quite different, which is more suitable for 'dotnet.config' IMO.

Ping @dotnet/templating-engine-maintainers @marcpopMSFT any concerns merging this?