feat: page Achievements + soins renommé + bouton soins en combat

Page /achievements : 20 succès groupés par catégorie (Combat, Progression,
Économie, Équipement), progress bars, paliers bronze/silver/gold,
bouton réclamer, compteur débloqués/total.

Renommage "repos" → "soins" partout (dashboard, budget, messages).
Bouton soins ajouté dans la page combat (accès rapide entre les fights).
Icône Trophy dans la sidebar pour les succès.

frontend/src/components/Layout.tsx

@@ -1,15 +1,16 @@
 import { Link, useLocation } from 'react-router-dom';
 import { useAuth } from '../context/AuthContext';
-import { Swords, Package, Hammer, User, LogOut, Shield, Scroll } from 'lucide-react';
+import { Swords, Package, Hammer, User, LogOut, Shield, Scroll, Trophy } from 'lucide-react';
 import { HudBar } from './HudBar';
 
 const NAV = [
-  { to: '/dashboard', icon: User,    label: 'Personnage' },
-  { to: '/quests',    icon: Scroll,  label: 'Quêtes' },
-  { to: '/combat',    icon: Swords,  label: 'Combat' },
-  { to: '/inventory', icon: Package, label: 'Inventaire' },
-  { to: '/craft',     icon: Hammer,  label: 'Artisanat' },
-  { to: '/forge',     icon: Shield,  label: 'Forge' },
+  { to: '/dashboard',    icon: User,    label: 'Personnage' },
+  { to: '/quests',       icon: Scroll,  label: 'Quêtes' },
+  { to: '/combat',       icon: Swords,  label: 'Combat' },
+  { to: '/inventory',    icon: Package, label: 'Inventaire' },
+  { to: '/craft',        icon: Hammer,  label: 'Artisanat' },
+  { to: '/forge',        icon: Shield,  label: 'Forge' },
+  { to: '/achievements', icon: Trophy,  label: 'Succès' },
 ];
 
 export function Layout({ children }: { children: React.ReactNode }) {