fix: Universal cover URIs, isolated markdown parsing, and category sh…

[lalalasupa0]

Description

This PR cleans up a few minor regressions and UI/UX formatting anomalies introduced in recent system changes:

1. Local Source Cover Resolution: Bypassing native URI generation previously broke standard file:// scheme attachments for Coil 3 on Primary Storage directories containing spaces, causing ENOENT silent failures. Prepending the scheme manually to filePath restores encoding compatibility across both Scoped and Primary directories without URL-encoding traps
   2. Category Sheet UI Dissipation (Category tab hides "cancel" and "move to" options when swiping downward #128): Re-added updateBottomButtons() translation math inside SetCategoriesSheet.kt. The dynamic translationY math bounds the Cancel/Move buttons safely above the navigation bar, preventing them from sliding completely off-screen on devices with dense lists (?)
2. Markdown Formatting Anomalies: Added dynamic text replacements in MangaHeaderHolder to convert < into < while utilizing negative lookaheads (?!!--) to preserve HTML comment invisibility (<!-- -->). This stops Markwon from interpreting E-Hentai tags as invisible HTML nodes. Also added a zero-width non-joiner (\u200C) escape for lone hyphens (-) and asterisks (*) to prevent single dashes from being swallowed as empty unordered list items

Checklist

• Code follows project style

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[lalalasupa0]

Hey @null2264 , just gently bumping this again. Noticed the reverted the math on the Category Sheet buttons earlier. I think I figured out the cause: the sheet was calculating the layout dimensions before the views fully finished drawing on screen, leaving a transparent gap. A 1-line update that safely re-triggers updateBottomButtons() via a post block after the layout pass may work, which makes them snap perfectly into place without touching your other logic