Revert "Remove InternalsVisibleTo for Toolkit"

[jfversluis]

Reverts #28994

Revert for now because the timing doesn't line up yet. We don't have a version of the Toolkit that uses the public types so with this change, the .NET 10 preview templates (using --sample-content) using the Toolkit will break immediately.

We probably want to think about maybe some pre-release of the Toolkit or maybe make the needed types public first, make the changes in the Toolkit and only then remove InternalsVisibleTo

Fixes #29320

[Copilot]

Pull Request Overview

This PR reverts a previous change that removed InternalsVisibleTo attributes for CommunityToolkit.Maui, ensuring that .NET 10 preview templates using the Toolkit do not break. Key changes include reintroducing the missing InternalsVisibleTo attributes in multiple AssemblyInfo files, restoring public/internal API boundaries in the PublicAPI.Unshipped.txt files, and reverting interface declaration modifications in Controls (e.g. ITextElement, ITextAlignmentElement, ILineHeightElement, ICornerElement).

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Essentials/src/AssemblyInfo/AssemblyInfo.shared.cs	Re-added InternalsVisibleTo attributes for CommunityToolkit.Maui assemblies.
src/Core/src/Properties/AssemblyInfo.cs	Reintroduced InternalsVisibleTo attributes; note duplicate declaration for Controls.TestCases.HostApp.
src/Controls/src/Xaml/Properties/AssemblyInfo.cs	Added InternalsVisibleTo attributes for CommunityToolkit.Maui assemblies.
PublicAPI.Unshipped.txt (various targets)	Adjusted public API listings to revert previous removals.
src/Controls/src/Core/ITextElement.cs, ITextAlignmentElement.cs, ILineHeightElement.cs, ICornerElement.cs	Reverted XML documentation and access modifiers changes on internal interfaces.

Comments suppressed due to low confidence (1)

src/Controls/src/Core/Properties/AssemblyInfo.cs:57

• There is a duplicate declaration for 'Controls.TestCases.HostApp'. Consider removing the redundant attribute to improve clarity and maintainability.

[assembly: InternalsVisibleTo("Controls.TestCases.HostApp")]

[PureWeen]

/backport to release/10.0.1xx-preview4

[github-actions]

Started backporting to release/10.0.1xx-preview4: https://github.com/dotnet/maui/actions/runs/14910467822