feat(ui): rebuild shared chrome and core browse/read pages

- Header: sticky app-wide, active nav highlighting, data-driven theme
  picker with active swatch, unified SVG icons, deduped login fragment
  (was duplicated verbatim for desktop + mobile), removed stray console.log
- LibrarySwitcher: cleaner sticky bar, SVG action icons, theme-aware
- BookCard: the atomic unit now has a real surface (was floating text
  when wood-paneling was off due to an undefined --wood-border), with
  cohesive shadow + hover lift; reused across dashboard/bookshelf/series
- Dashboard: calmer section headers, snap carousels with SVG chevrons
- Bookshelf: recompose the filter wall into a search toolbar + collapsible
  Filters panel (all 9 filters + save/load/clear preserved), redesigned
  empty state and pagination
- Book detail, series, collections, browse: cohesive cards, SVG action
  icons, uppercase muted labels, theme-aware badges/links

templates/books_grid_templ.go

@@ -39,7 +39,15 @@ func BooksGrid(books []handlers.BookInfo, limit int, offset int, count int, curr
 				}
 			}
 		} else {
-			templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 1, "<!-- Empty state --> <div class=\"col-span-full text-center py-12\" style=\"color: var(--text-secondary);\"><p class=\"text-lg mb-2\">📚 No books found</p><p class=\"text-sm\">Try adjusting your filters or add some books to your library.</p></div>")
+			templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 1, "<div class=\"col-span-full flex flex-col items-center justify-center rounded-2xl border border-dashed border-line py-16 text-center\"><div class=\"mb-3 flex h-14 w-14 items-center justify-center rounded-full bg-surface-hover text-content-muted\">")
+			if templ_7745c5c3_Err != nil {
+				return templ_7745c5c3_Err
+			}
+			templ_7745c5c3_Err = Icon("book", "h-7 w-7").Render(ctx, templ_7745c5c3_Buffer)
+			if templ_7745c5c3_Err != nil {
+				return templ_7745c5c3_Err
+			}
+			templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 2, "</div><p class=\"text-base font-semibold text-content\">No books found</p><p class=\"mt-1 text-sm text-content-muted\">Try adjusting your filters or add some books to your library.</p></div>")
 			if templ_7745c5c3_Err != nil {
 				return templ_7745c5c3_Err
 			}