- Add `ChapterWithPages` model and `MangaReaderController` (FamilyAsyncNotifier)
to load chapter + pages in a single provider (`mangaReaderProvider`)
- Replace synchronous Isar fetch in `MangaReaderView` with `ref.watch(mangaReaderProvider)`
- Unify loading, error, and data states using a shared `scaffoldWith` helper
- Remove duplicated `Scaffold`/`AppBar` boilerplate and inline SystemChrome restore logic
- Simplify error handling
At line 963, when scrolling too fast in manga reader and page didn't load before.
```
═══════ Exception caught by foundation library ════════════════════════════════
The following StateError was thrown while dispatching notifications for ValueNotifier<Iterable<ItemPosition>>:
Bad state: No element
```
```
════════ Exception caught by widgets library ═══════════════════════════════════
The following UnsupportedError was thrown building CircularProgressIndicator(100.0%, dependencies: [InheritedCupertinoTheme, _InheritedTheme, _LocalizationsScope-[GlobalKey#3b6da]], state: _CircularProgressIndicatorState#8c03b(ticker inactive)):
Unsupported operation: Infinity or NaN toInt
The relevant error-causing widget was:
CircularProgressIndicator CircularProgressIndicator (package:mangayomi/modules/manga/reader/widgets/circular_progress_indicator_animate_rotate.dart:56:27)
```
- Missed a concatenated path in manga_detail_view and in reader_view
- Made the Manga / Anime title selectable, so one can copy the title if needed
- Hidden the Backup share-button, because Linux has no share-feature and the button simply does nothing.
