feat: add multi-provider support (Komga + Stripstream Librarian)

- Introduce provider abstraction layer (IMediaProvider, KomgaProvider, StripstreamProvider)
- Add Stripstream Librarian as second media provider with full feature parity
- Migrate all pages and components from direct Komga services to provider factory
- Remove dead service code (BaseApiService, HomeService, LibraryService, SearchService, TestService)
- Fix library/series page-based pagination for both providers (Komga 0-indexed, Stripstream 1-indexed)
- Fix unread filter and search on library page for both providers
- Fix read progress display for Stripstream (reading_status mapping)
- Fix series read status (books_read_count) for Stripstream
- Add global search with series results for Stripstream (series_hits from Meilisearch)
- Fix thumbnail proxy to return 404 gracefully instead of JSON on upstream error
- Replace duration-based cache debug detection with x-nextjs-cache header

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/actions/books.ts

@@ -1,36 +1,40 @@
 "use server";
 
-import { BookService } from "@/lib/services/book.service";
+import { getProvider } from "@/lib/providers/provider.factory";
 import { AppError } from "@/utils/errors";
-import type { KomgaBook } from "@/types/komga";
+import type { NormalizedBook } from "@/lib/providers/types";
 import logger from "@/lib/logger";
 
 interface BookDataResult {
   success: boolean;
   data?: {
-    book: KomgaBook;
+    book: NormalizedBook;
     pages: number[];
-    nextBook: KomgaBook | null;
+    nextBook: NormalizedBook | null;
   };
   message?: string;
 }
 
 export async function getBookData(bookId: string): Promise<BookDataResult> {
   try {
-    const data = await BookService.getBook(bookId);
-    let nextBook = null;
+    const provider = await getProvider();
+    if (!provider) {
+      return { success: false, message: "KOMGA_MISSING_CONFIG" };
+    }
+
+    const book = await provider.getBook(bookId);
+    const pages = Array.from({ length: book.pageCount }, (_, i) => i + 1);
+
+    let nextBook: NormalizedBook | null = null;
     try {
-      nextBook = await BookService.getNextBook(bookId, data.book.seriesId);
+      nextBook = await provider.getNextBook(bookId);
     } catch (error) {
       logger.warn({ err: error, bookId }, "Failed to fetch next book in server action");
     }
 
     return {
       success: true,
-      data: {
-        ...data,
-        nextBook,
-      },
+      data: { book, pages, nextBook },
     };
   } catch (error) {
     if (error instanceof AppError) {