Add missing seasons endpoint and update metadata handling

Implemented a new endpoint to retrieve missing seasons for shows, enhancing the MetadataEndpoints class. Updated the IMetadataProvider interface to include a method for fetching season numbers. Adjusted the ShowSummaryDto to include other genres and modified the ListShowsQueryHandler to handle multiple genres. Enhanced the Omdb and Tmdb metadata providers to support season number retrieval. Updated frontend components to integrate missing seasons functionality, including API calls and UI elements for displaying missing seasons reports.

frontend/src/features/admin/shows/api.ts

@@ -3,6 +3,7 @@ import type {
   CreatedIdResponse,
   MetadataCandidate,
   MissingEpisodesReport,
+  MissingSeasonsReport,
   ShowAudience,
   ShowDto,
   ShowKind,
@@ -114,3 +115,8 @@ export function refreshEpisodesMetadata(showId: string) {
 export function findMissingEpisodes(showId: string) {
   return apiRequest<MissingEpisodesReport>(`/admin/metadata/shows/${showId}/missing-episodes`)
 }
+
+/** Отчёт: каких сезонов нет в библиотеке вовсе (по данным источника). */
+export function findMissingSeasons(showId: string) {
+  return apiRequest<MissingSeasonsReport>(`/admin/metadata/shows/${showId}/missing-seasons`)
+}