fix: cover proxy routing, session filtering, library tab deep-link, profile UX

- Catalogue/cover: rewrite raw scraped cover URLs to /api/cover/{domain}/{slug}
  in handleCatalogue so all covers route through the backend proxy; fix broken
  cdn.novelfire.net fallback in handleGetCover to read stored URL from PocketBase
- Catalogue/profile: add Svelte 5 onerror handlers on cover <img> tags to show
  letter-initial placeholder when image fails to load
- Library page: read ?status URL param to initialise activeShelf tab on load so
  /books?status=reading correctly pre-selects the Reading tab
- Sessions: filter bot/tool user-agents (curl, python, wget, etc.) and debug-IP
  sessions from listUserSessions display; also purge them in pruneStaleUserSessions
- Profile: show email under username, quick stats chips (streak/chapters/completed)
  in header, reading count on Library row, dedicated Sign out row, history covers
  routed through /api/cover proxy

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

backend/internal/backend/handlers.go

@@ -293,7 +293,8 @@ func (s *Server) handleGetRanking(w http.ResponseWriter, r *http.Request) {
 
 // handleGetCover handles GET /api/cover/{domain}/{slug}.
 // Serves the cover image directly from MinIO when available; falls back to a
-// redirect to the novelfire CDN when the cover has not yet been downloaded.
+// redirect to the stored cover URL from PocketBase when the cover has not yet
+// been downloaded to MinIO.
 func (s *Server) handleGetCover(w http.ResponseWriter, r *http.Request) {
 	slug := r.PathValue("slug")
 	if slug == "" {
@@ -318,10 +319,20 @@ func (s *Server) handleGetCover(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// Fallback: redirect to the CDN. The caller sees a working image; the
-	// cover will be populated on the next catalogue refresh run.
-	coverURL := fmt.Sprintf("https://cdn.novelfire.net/covers/%s.jpg", slug)
-	http.Redirect(w, r, coverURL, http.StatusFound)
+	// Fallback: read the stored cover URL from PocketBase and redirect to it.
+	// This avoids the broken cdn.novelfire.net domain and uses the actual URL
+	// scraped from the source. If the book is not found, return 404.
+	meta, ok, err := s.deps.BookReader.ReadMetadata(r.Context(), slug)
+	if err != nil {
+		s.deps.Log.Warn("handleGetCover: ReadMetadata error", "slug", slug, "err", err)
+		http.Error(w, "cover not found", http.StatusNotFound)
+		return
+	}
+	if !ok || meta.Cover == "" || strings.HasPrefix(meta.Cover, "/api/cover/") {
+		http.Error(w, "cover not found", http.StatusNotFound)
+		return
+	}
+	http.Redirect(w, r, meta.Cover, http.StatusFound)
 }
 
 // ── Preview (live scrape, no store writes) ─────────────────────────────────────
@@ -1891,6 +1902,16 @@ func (s *Server) handleCatalogue(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Rewrite raw scraped cover URLs to go through the backend cover proxy.
+	// /api/cover/{domain}/{slug} serves from MinIO when available, otherwise
+	// redirects to the CDN. This avoids ERR_BLOCKED_BY_ORB when the source
+	// site returns HTML error pages instead of images.
+	for i := range books {
+		if !strings.HasPrefix(books[i].Cover, "/api/cover/") {
+			books[i].Cover = fmt.Sprintf("/api/cover/novelfire.net/%s", books[i].Slug)
+		}
+	}
+
 	hasNext := int64(page*limit) < total
 
 	w.Header().Set("Cache-Control", "public, max-age=60")