Prefer English edition in ratings-based edition selection tiebreak

[jbob06]

Bug

When an import list discovers a new author from one shelved book, Chaptarr pulls in that author's entire back-catalog as unmonitored stub Book rows. For each work, EditionSelector has to pick one edition to represent it in the local catalog — and that pick had no language preference at all: it ranked candidates purely by native-format match, then per-edition vote count.

MetadataProfile.AllowedLanguages only filters the candidate pool when it's explicitly configured. On the common unconfigured profile, every language passes through untouched, and a translated edition can end up with more votes on its own edition row than the original English one for the same work (e.g. all Spanish-reader votes on one edition row, while English votes are split across several English edition rows). The higher-voted foreign edition then wins and gets stored as the book's sole representative edition.

Concretely, this produced local catalog rows like:

• A book whose local title became "<Title> [Spanish Edition]", its stored edition carrying Spanish narrator credits, despite an English edition of the same work being available
• A book whose local title became "<Title> – <German subtitle>", similarly mismatched

Both cases trace to the same author-bibliography-refresh timestamp in the DB, confirming the bulk back-catalog path, not a one-off manual add.

This selector (EditionSelector.SelectByNativeFormatThenRatings, via SelectMostRated/SelectRepresentativeFallback) is shared by two call sites:

• BookInfoProxy.SelectBestEditionAsMonitored — the provisional pick made when converting an author's full back-catalog from provider data, explicitly commented as provisional ("Language ... filtering happen[s] later once the metadata profile is available")
• AuthorLibraryService.SelectMonitoredEditionsForMediaType — the later, profile-aware pick

Unmonitored bibliography stub books never get promoted to the second pass, so they stay stuck with whatever the language-blind provisional pick chose — permanently.

Fix

Add a language-preference tiebreak ahead of vote count in SelectMostRated and SelectRepresentativeFallback: an edition with explicit English language wins, an edition with no language tag is treated neutrally (not punished for missing metadata), and any other explicit language loses. It's a soft default ordering key, not an exclusionary filter — a foreign-only candidate pool still falls back to picking by votes exactly as before, and a library where AllowedLanguages is explicitly restricted to something else still narrows correctly upstream in EditionMetadataProfileFilter.

Added tests in EditionSelectorLanguageFilteringFixture covering: English winning over a more-voted foreign edition for both audiobook and ebook media types, and the no-English-available fallback still picking by votes.

Testing

Ran dotnet test (net10.0) locally: full suite passes, 3023/3023, 0 failures — including the 3 new tests in EditionSelectorLanguageFilteringFixture.

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