Breaking change docs: TarWriter now emits HardLink entries for hard-linked files (.NET 11)

[Copilot]

Documents the .NET 11 Preview 3 behavioral change where TarWriter writes HardLink entries for files sharing the same inode instead of duplicating content—aligning with GNU tar behavior.

Changes

• New article docs/core/compatibility/core-libraries/11/tarwriter-hardlink-entries.md — covers previous/new behavior, reason for change, and migration path
• TOC (toc.yml) — new entry under .NET 11 Core .NET libraries
• Index (11.md) — new row in Core .NET libraries table

Key migration guidance

If content duplication is required, use the new TarWriterOptions.HardLinkMode:

var options = new TarWriterOptions(TarEntryFormat.Pax)
{
    HardLinkMode = TarHardLinkMode.CopyContents
};

using var writer = new TarWriter(stream, options, leaveOpen: false);

Also notes that extracting HardLink entries on file systems without hard link support throws IOException, and that .NET 11's new TarExtractOptions can be used to control extraction behavior.

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Changes:

• New article: docs/core/compatibility/core-libraries/11/tarwriter --noprofile (http block)

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---

Internal previews

📄 File	🔗 Preview link
docs/core/compatibility/11.md	Breaking changes in .NET 11
docs/core/compatibility/core-libraries/11/tarwriter-hardlink-entries.md	TarWriter uses HardLink entries for hard-linked files
docs/core/compatibility/toc.yml	docs/core/compatibility/toc

[Copilot]

Pull request overview

Adds a new .NET 11 breaking-change article documenting updated System.Formats.Tar.TarWriter behavior for hard-linked files (subsequent entries become HardLink entries instead of duplicating contents), and wires the article into the compatibility navigation and index.

Changes:

• Adds a new breaking change article for TarWriter hard-link handling in .NET 11 Preview 3.
• Updates docs/core/compatibility/toc.yml to include the new article under .NET 11 Core .NET libraries.
• Updates docs/core/compatibility/11.md to list the new breaking change in the Core .NET libraries table.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
docs/core/compatibility/toc.yml	Adds the new breaking change article to the .NET 11 Core .NET libraries TOC.
docs/core/compatibility/core-libraries/11/tarwriter-hardlink-entries.md	New breaking change article describing the TarWriter hard-link entry behavior and mitigation option.
docs/core/compatibility/11.md	Adds the new breaking change entry to the .NET 11 index table.

[BillWagner]

This LGTM. I have one question for you to consider.

[rzikm]

LGTM modulo existing comments