Add ARJ and ARC decompression support

[Copilot]

SharpCompress 0.42.0+ added ARJ and ARC archive support. This PR integrates these formats into RecursiveExtractor.

Changes

Core

• Bump SharpCompress 0.40.0 → 0.44.3
• Add ARJ and ARC to ArchiveFileType enum
• Register extractors in SetDefaultExtractors()

Magic byte detection (MiniMagic.cs)

• ARJ: 0x60 0xEA at offset 0
• ARC: 0x1A + compression method (≤0x0B) at offset 0

Extractors

• ArjExtractor.cs - Uses SharpCompress.Readers.Arj.ArjReader
• ArcExtractor.cs - Uses SharpCompress.Readers.Arc.ArcReader with workaround for unimplemented Size property

Tests

• Added TestData.arj and TestData.arc test archives
• Added entries to ExpectedNumFilesTests and MiniMagicTests

Usage

var extractor = new Extractor();
var files = extractor.Extract("archive.arj", new ExtractorOptions());
// or
var files = extractor.Extract("archive.arc", new ExtractorOptions());

Notes

• ARJ/ARC use Reader API (forward-only) since SharpCompress doesn't provide Archive API for these formats

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add ARJ decompression, provided by SharpCompress</issue_title>
<issue_description>SharpCompress supports ARC and ARJ decompression starting from version 0.42.0. Would be great if RecursiveExtractor also supports these formats.</issue_description>

<agent_instructions>Please try to add support for these new formats recently added to sharpcompress. https://github.com/adamhathcock/sharpcompress. Make sure to bump the sharpcompress dependency to the latest version, and follow the existing patterns for implementing minimagic detection for the new archive types (checking for header/footer signature as appropriate for the new archive type) adding an archive file type to the enum and adding an extractor matching the existing interface patterns.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Add ARJ decompression, provided by SharpCompress #180

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[gfs]

@copilot revert the change to nuget.config

[Copilot]

@copilot revert the change to nuget.config

Reverted in 5693355.