Add new LinkRelation for the readingOrder and EPUB landmarks

[mickael-menu]

Added

Navigator

• New link rels in the readingOrder and EPUB landmarks to mark:
  • cover: the title page
  • contents: the table of contents
  • start: the first actual chapter

[Copilot]

Pull Request Overview

This PR adds a new EPUB landmark link relation for the reading order by introducing a new LinkRelation (.start) and updating namespace definition usage throughout the EPUB parser modules. Key changes include:

• Replacing explicit namespace string definitions with centralized defineNamespace/defineNamespaces calls.
• Refactoring OPF and EPUB parsers to use the new namespace APIs.
• Adding a new LinkRelation+EPUB extension to map EPUB-specific link types.

Reviewed Changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Sources/Streamer/Parser/EPUB/XMLNamespace.swift	Added helper extensions for defining one or multiple XML namespaces.
Sources/Streamer/Parser/EPUB/OPFParser.swift	Updated namespace calls to use defineNamespace.
Sources/Streamer/Parser/EPUB/OPFMeta.swift	Replaced explicit namespace calls with defineNamespace(s).
Sources/Streamer/Parser/EPUB/NavigationDocumentParser.swift	Updated namespace usage and passed the new LinkRelation (via epubType) to makeLink.
Sources/Streamer/Parser/EPUB/NCXParser.swift	Refactored namespace initialization using defineNamespace.
Sources/Streamer/Parser/EPUB/Extensions/LinkRelation+EPUB.swift	Added EPUB-specific initializer for LinkRelation based on epubType.
Sources/Streamer/Parser/EPUB/EPUBParser.swift	Refactored publication parsing to use EPUBManifestParser and updated deobfuscator initialization.
Sources/Streamer/Parser/EPUB/EPUBMetadataParser.swift	Updated namespace calls to use defineNamespace(s).
Sources/Streamer/Parser/EPUB/EPUBManifestParser.swift	Introduced a new manifest parser that fills in readingOrder link relations based on landmarks.
Sources/Streamer/Parser/EPUB/EPUBEncryptionParser.swift	Updated namespace usage with defineNamespace.
Sources/Streamer/Parser/EPUB/EPUBContainerParser.swift	Updated namespace definition to use defineNamespace.
Sources/Shared/Toolkit/XML/XML.swift	Refactored XMLNamespace into a structured type with predefined constants.
Various Sniffer files	Updated inline XML namespace definitions to use the centralized XMLNamespace constants.
Sources/Shared/Publication/LinkRelation.swift	Added the new .start link relation to support landmark entries.
Sources/OPDS/XMLNamespace.swift and Sources/OPDS/OPDS1Parser.swift	Updated namespace definitions with defineNamespace calls.
CHANGELOG.md	Documented the new link relations for readingOrder landmarks.