Fix memory leaks

[mickael-menu]

• Fix memory leaks using memoize().
• Fix memory leaks in the EPUB navigator.
• Display the initial decorations faster in the EPUB navigator.

[Copilot]

Pull Request Overview

This PR addresses memory leaks by replacing the legacy memoization pattern with Swift Tasks across multiple services and view controllers. Key changes include:

• Replacing memoize calls with Task-based asynchronous initializations in PDF and EPUB services.
• Updating asynchronous patterns in content iterators, navigators, and view controllers to improve lifecycle management.
• Removing the legacy memoize implementation in favor of Task-based methods to mitigate memory retention issues.

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Sources/Streamer/Parser/PDF/Services/LCPDFTableOfContentsService.swift	Replaces memoize call with a Task-based property for generating the table of contents.
Sources/Streamer/Parser/PDF/Services/LCPDFPositionsService.swift	Uses Task-based caching for computing positions by reading order.
Sources/Shared/Publication/Services/Content/Iterators/HTMLResourceContentIterator.swift	Updates memoization of elements and total progression range to Task-based asynchronous properties.
Sources/Navigator/Toolkit/PaginationView.swift	Introduces lifecycle handling in didMoveToWindow and converts async calls to synchronous ones where applicable.
Sources/Navigator/EPUB/EPUBSpreadView.swift, EPUBReflowableSpreadView.swift, EPUBFixedSpreadView.swift	Updates spread loading flags and delegate callbacks to follow async patterns consistently.
Sources/Navigator/EPUB/EPUBNavigatorViewController.swift	Refactors table of contents title retrieval and spread reloading without awaiting, aligning with updated async workflows.
Sources/LCP/Content Protection/LCPDecryptor.swift	Adopts Task-based initialization for calculating plain text size.
Sources/Internal/Memoize.swift	Removed in favor of Task-based approaches.
Sources/Internal/Extensions/Task.swift	Adds helper methods for task management and replacement.

Comments suppressed due to low confidence (1)

Sources/Navigator/Toolkit/PaginationView.swift:222

• [nitpick] Converting asynchronous calls to synchronous ones in 'setCurrentIndex' and related methods may affect UI update timing. Verify that these changes maintain UI responsiveness and do not block the main thread.

loadPages()