Users can now add Mangas/Animes to a **manually** created Mangayomi/local folder.
Feature as described:
```
App Home Location/
local/
Manga Title/
cover.jpg (optional)
Chapter 1/
1.jpg
...
Chapter 2.cbz
...
Anime Title/
cover.png (optional)
Episode 1.mp4
Episode 2.mkv
```
The folder (if exist) will be scanned once per app start.
**Supported filetypes:** (taken from lib/modules/library/providers/local_archive.dart, line 98)
```
Videotypes: mp4, mov, avi, flv, wmv, mpeg, mkv
Imagetypes: jpg, jpeg, png, webp
Archivetypes: cbz, zip, cbt, tar
```
getMangaChapterDirectory() now accepts an optional mangaMainDirectory
to avoid calling getMangaMainDirectory() and thus getDirectory() twice in places where both methods are called successively.
- 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)
```
