feat: in-reader settings, more like this, reading history, audio filter, feed page

- Add floating gear button + theme/font/size drawer in chapter reader
- Add 'More like this' horizontal scroll row on book detail page
- Add reading history tab on profile page (chronological progress timeline)
- Add audio-available badge + filter toggle on catalogue (GET /api/audio/slugs)
- Fix discover card entry animation pop (split entry vs snap-back cubic-bezier)
- Add dedicated /feed page showing books followed users are reading
- Add Feed nav link (desktop + mobile) in all 5 locales

ui/messages/fr.json

@@ -3,6 +3,7 @@
 
   "nav_library": "Bibliothèque",
   "nav_catalogue": "Catalogue",
+  "nav_feed": "Fil",
   "nav_feedback": "Retour",
   "nav_admin": "Admin",
   "nav_profile": "Profil",
@@ -418,5 +419,16 @@
   "profile_text_size_sm": "Petit",
   "profile_text_size_md": "Normal",
   "profile_text_size_lg": "Grand",
-  "profile_text_size_xl": "Très grand"
+  "profile_text_size_xl": "Très grand",
+
+  "feed_page_title": "Fil — LibNovel",
+  "feed_heading": "Fil d'abonnements",
+  "feed_subheading": "Livres lus par vos abonnements",
+  "feed_empty_heading": "Rien encore",
+  "feed_empty_body": "Suivez d'autres lecteurs pour voir ce qu'ils lisent.",
+  "feed_not_logged_in": "Connectez-vous pour voir votre fil.",
+  "feed_reader_label": "lit",
+  "feed_chapters_label": "{n} chapitres",
+  "feed_browse_cta": "Parcourir le catalogue",
+  "feed_find_users_cta": "Trouver des lecteurs"
 }