OPDS Flattening (#1904)

* Flattening OPDS Structure

# Changed
- Flattened OPDS structure to reduce user taps.

* Fixing format

* Fixing book series titles

* Optimized file size to use pre-calculated data to avoid an I/O touch.

* Fixes #1898 by aligning all content headers to the correct MIME types

* Remove dead code

* Fixed a bug with continue point where it fails on chapters or volumes tagged with a range

---------

Co-authored-by: Robbie Davis <robbie@therobbiedavis.com>

API.Tests/Services/ReaderServiceTests.cs

@@ -1366,6 +1366,45 @@ public class ReaderServiceTests
         Assert.Equal("1", nextChapter.Range);
     }
 
+    [Fact]
+    public async Task GetContinuePoint_ShouldReturnFirstVolume_WhenFirstVolumeIsAlsoTaggedAsChapter1Through11_WithProgress()
+    {
+        await ResetDb();
+        var series = new SeriesBuilder("Test")
+            .WithVolume(new VolumeBuilder("1")
+                .WithChapter(new ChapterBuilder("1", "1-11").WithPages(3).Build())
+                .Build())
+            .WithVolume(new VolumeBuilder("2")
+                .WithChapter(new ChapterBuilder("0").WithPages(1).Build())
+                .Build())
+            .WithPages(4)
+            .Build();
+        series.Library = new LibraryBuilder("Test LIb", LibraryType.Manga).Build();
+
+        _context.Series.Add(series);
+
+        _context.AppUser.Add(new AppUser()
+        {
+            UserName = "majora2007"
+        });
+
+        await _context.SaveChangesAsync();
+
+
+
+
+        await _readerService.SaveReadingProgress(new ProgressDto()
+        {
+            PageNum = 2,
+            ChapterId = 1,
+            SeriesId = 1,
+            VolumeId = 1
+        }, 1);
+        var nextChapter = await _readerService.GetContinuePoint(1, 1);
+
+        Assert.Equal("1-11", nextChapter.Range);
+    }
+
     [Fact]
     public async Task GetContinuePoint_ShouldReturnFirstNonSpecial()
     {