feat(series): add selectable cover modes for collapsed series cards

Allow readers to choose which representative series cover appears in collapsed grid view so browsing can prioritize first, latest, or first unread volumes.

Closes #160

packages/types/src/display-preferences.ts

@@ -22,6 +22,9 @@ export type BookShadowStrength = (typeof BOOK_SHADOW_STRENGTHS)[number];
 export const BOOK_COVER_DISPLAY_MODES = ["blurred-fit", "fill-crop", "natural-bottom"] as const;
 export type BookCoverDisplayMode = (typeof BOOK_COVER_DISPLAY_MODES)[number];
 
+export const SERIES_CARD_COVER_MODES = ["mosaic", "first-volume", "latest-volume", "first-unread"] as const;
+export type SeriesCardCoverMode = (typeof SERIES_CARD_COVER_MODES)[number];
+
 export interface DisplayPreferences {
   portraitCoverSize: number;
   squareCoverSize: number;
@@ -39,4 +42,5 @@ export interface DisplayPreferences {
   bookSpineOverlay: BookSpineOverlay;
   bookShadowStrength: BookShadowStrength;
   bookCoverDisplayMode: BookCoverDisplayMode;
+  seriesCardCoverMode: SeriesCardCoverMode;
 }

packages/types/src/series-collapse.ts

@@ -9,6 +9,9 @@ export type CollapsedSeriesInfo = {
   readCount: number;
   coverBookIds: number[];
   seriesLatestAddedAt: string | null;
+  firstVolumeBookId?: number | null;
+  latestVolumeBookId?: number | null;
+  firstUnreadBookId?: number | null;
 };
 
 export function resolveCollapsePreference(prefs: SeriesCollapsePreferences | undefined, ctx: { libraryId?: number; collectionId?: number }): boolean {