fix(ebook-reader): load SVG images and fix progress update ID

- Add SVG image support: process <image xlink:href=...> elements
  in addition to HTML <img> tags for cover pages and embedded images
- Fix progress update: use 'id' from API response instead of
  'media_item_id' which the backend never returns for this endpoint
- Update reader context interfaces to include currentPage field
- Add debug logging for all resource keys to help troubleshoot
  image loading issues in future epubs

web/src/reader/core/reader-context.ts

@@ -28,7 +28,11 @@ interface MangaReader {
   readingDirection: "rtl" | "vertical";
 }
 
-type CurrentReader = UniversalReader | PDFReader | ComicReader | MangaReader;
+export type CurrentReader =
+  | UniversalReader
+  | PDFReader
+  | ComicReader
+  | MangaReader;
 
 export interface ReaderContext {
   getState: () => {