Change the precedence of EPUB series

[mickael-menu]

Changed

Streamer

• EPUB series added with Calibre now take precedence over the native EPUB ones in the belongsToSeries RWPM property.

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The reason for this change is that a user editing a publication with Calibre will want the reading app to use its custom series instead of the EPUB ones.

[Copilot]

Pull Request Overview

This PR changes the precedence order for EPUB series metadata, making Calibre-added series take priority over native EPUB series data. It also includes a fix for RelativeURL resolution behavior on iOS 26.

• Changes series precedence logic to prioritize Calibre metadata over native EPUB series
• Fixes RelativeURL resolution to handle unwanted leading slashes on iOS 26
• Updates test expectations to reflect the corrected URL behavior

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
Sources/Streamer/Parser/EPUB/EPUBMetadataParser.swift	Restructures series metadata parsing to check Calibre series first, then fall back to EPUB3 series
Sources/Shared/Toolkit/URL/RelativeURL.swift	Adds iOS 26 compatibility fix for URL resolution that removes unwanted leading slashes
Tests/SharedTests/Toolkit/URL/RelativeURLTests.swift	Updates test expectation for root path removal behavior
CHANGELOG.md	Documents the series precedence change

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