feat(reader): add reader API integration

- Add getReaderMetadata() to fetch media item metadata
- Add updateReadingProgress() to sync reading progress to backend
- Export ReaderMetadata and ReadingProgress types
- Enable reader to communicate with Go backend

web/src/api.ts

@@ -88,6 +88,48 @@ function handleError(error: unknown, context: string): void {
   showToast(message, "error");
 }
 
+// ============================================================
+// Reader API Functions
+// ============================================================
+interface ReaderMetadata {
+  media_item_id: string;
+  title: string;
+  author: string;
+  cover_image_path: string;
+  library_type: "ebook" | "comic" | "manga" | "pdf";
+  mime_type: string;
+  file_path: string;
+  chapter_metadata?: ChapterMetadata;
+  total_pages?: number;
+}
+interface ChapterMetadata {
+  chapters: Chapter[];
+}
+interface Chapter {
+  id: string;
+  title: string;
+  start_page: number;
+  page_count: number;
+}
+interface ReadingProgress {
+  current_page: number;
+  total_pages: number;
+}
+async function getReaderMetadata(mediaItemId: string): Promise<ReaderMetadata> {
+  const response = await apiGet(`/media-items/${mediaItemId}`);
+  return handleResponse<ReaderMetadata>(response);
+}
+async function updateReadingProgress(
+  mediaItemId: string,
+  progress: ReadingProgress,
+): Promise<void> {
+  const response = await apiPut(
+    `/media-items/${mediaItemId}/progress`,
+    progress,
+  );
+  await handleVoidResponse(response);
+}
+
 export {
   apiGet,
   apiPost,
@@ -97,6 +139,12 @@ export {
   handleResponse,
   handleVoidResponse,
   handleError,
+  getReaderMetadata,
+  updateReadingProgress,
+  ReaderMetadata,
+  ReadingProgress,
+  ChapterMetadata,
+  Chapter,
 };
 
 Alpine.data("api", () => ({