✨ feat(mobile): add BottomBar navigation and CheminLibre drawer (Story 3.7)

- Add ZoneCard component for zone display with status indicators
- Add CheminLibre drawer with vertical zone cards and path decoration
- Add BottomBar with Map, Progress, and Settings buttons
- Add ProgressDetail modal showing visited sections
- Add SettingsDrawer with language, consent, and reset options
- Add i18n translations for zone, cheminLibre, bottomBar, settings
- Add --bottom-bar-height CSS variable for spacing
- Modify layouts to include BottomBar on mobile (< 768px)
- Support safe-area-inset for iOS devices
- Touch targets minimum 48x48px for WCAG compliance

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/i18n/fr.json

@@ -202,6 +202,31 @@
     },
     "summary": "{visited} visité(s), {remaining} à découvrir"
   },
+  "zone": {
+    "locked": "Verrouillé",
+    "visited": "Visité",
+    "new": "À découvrir",
+    "newBadge": "Nouveau"
+  },
+  "cheminLibre": {
+    "title": "Chemin Libre"
+  },
+  "bottomBar": {
+    "map": "Carte",
+    "progress": "Progression",
+    "settings": "Options"
+  },
+  "settings": {
+    "title": "Paramètres",
+    "language": "Langue",
+    "expressMode": "Mode Express",
+    "expressModeDesc": "Navigation rapide sans aventure",
+    "goToResume": "Voir le CV",
+    "saveProgress": "Sauvegarder ma progression",
+    "saveProgressDesc": "Permet de reprendre là où vous vous êtes arrêté",
+    "reset": "Réinitialiser ma progression",
+    "confirmReset": "Êtes-vous sûr de vouloir réinitialiser votre progression ?"
+  },
   "pages": {
     "projects": {
       "title": "Projets",