feat: add show more/less toggle for series description

Allow users to expand long series descriptions with a "Show more" button
and scroll through the full text, instead of being limited to 3 lines.

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

src/i18n/messages/en/common.json

@@ -261,6 +261,8 @@
         "add": "Added to favorites",
         "remove": "Removed from favorites"
       },
+      "showMore": "Show more",
+      "showLess": "Show less",
       "toggleSidebar": "Toggle sidebar",
       "toggleTheme": "Toggle theme"
     }

src/i18n/messages/fr/common.json

@@ -260,7 +260,9 @@
       "favorite": {
         "add": "Ajouté aux favoris",
         "remove": "Retiré des favoris"
-      }
+      },
+      "showMore": "Voir plus",
+      "showLess": "Voir moins"
     }
   },
   "books": {