Two changes to EPUB metadata extraction:
1. Restructure extractMetadata so that fixed-layout detection and cover
extraction always run for EPUBs, even when extractEPUBMetadata returns
an error. Previously, a partial failure from the EPUB parser would skip
cover and format detection entirely, leaving books without covers.
2. Remove the language restriction (ja/jpn) from manga reading direction
detection. Manga tagged with 'manga' should default to RTL regardless
of the language metadata, since the tag is an explicit signal from the
user or metadata source.
john-okeefe
5b2d105609