feat: multi-combat ×5/×10 + cooldown anti-spam

- Backend: startMultiCombat boucle séquentielle, arrêt sur défaite
- Frontend: cooldown 1.5s entre combats, boutons ×1/×5/×10
- Frontend: résumé multi-combat (wins/losses, XP/Or/loot totaux)
- Fix: lock contention par spam de clics résolu

frontend/src/pages/CombatPage.tsx

@@ -1,7 +1,7 @@
-import { useState } from 'react';
+import { useState, useEffect, useCallback } from 'react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { combatApi, characterApi } from '../api/endpoints';
-import type { Monster, CombatResult, CombatLog } from '../api/types';
+import type { Monster, CombatResult, MultiCombatResult, CombatLog } from '../api/types';
 import { Swords, Trophy, Skull, Clock, Zap, Heart, Lock } from 'lucide-react';
 
 const COMBAT_COST = 5;
@@ -91,6 +91,39 @@ function CombatLogView({ result }: { result: CombatResult }) {
   );
 }
 
+function MultiCombatView({ result }: { result: MultiCombatResult }) {
+  const t = result.totals;
+  return (
+    <div className="card" style={{ marginTop: '1rem' }}>
+      <div style={{ textAlign: 'center', padding: '0.75rem 0', marginBottom: '0.75rem', borderBottom: '1px solid #2a3448' }}>
+        <div style={{ fontWeight: 800, fontSize: 18, color: t.losses > 0 ? '#e84040' : '#3ddc84' }}>
+          {t.losses > 0 ? <Skull size={20} style={{ display: 'inline', marginRight: 8 }} /> : <Trophy size={20} style={{ display: 'inline', marginRight: 8 }} />}
+          {result.count} combat{result.count > 1 ? 's' : ''} — {t.wins}V / {t.losses}D
+        </div>
+        <div style={{ fontSize: 14, color: '#dce4f0', marginTop: 6 }}>
+          +{t.xp} XP  +{t.gold} Or
+          {t.goldLost > 0 && <span style={{ color: '#e84040' }}>  −{t.goldLost} Or</span>}
+        </div>
+        {t.levelsGained > 0 && (
+          <div style={{ fontSize: 13, color: '#a78bfa', marginTop: 4 }}>
+            🎉 {t.levelsGained} level up{t.levelsGained > 1 ? 's' : ''} !
+          </div>
+        )}
+        {t.loot.length > 0 && (
+          <div style={{ fontSize: 13, color: '#f4c94e', marginTop: 4 }}>
+            🎁 Loot : {t.loot.reduce((sum, l) => sum + l.quantity, 0)} matériaux
+          </div>
+        )}
+        {t.losses > 0 && (
+          <div style={{ fontSize: 11, color: '#6b7a99', marginTop: 4 }}>
+            Série interrompue par une défaite
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}
+
 function HistoryEntry({ h }: { h: CombatLog }) {
   return (
     <div style={{ display: 'flex', justifyContent: 'space-between', fontSize: 12, padding: '3px 0', borderBottom: '1px solid #1e2535' }}>
@@ -109,6 +142,8 @@ export function CombatPage() {
   const [selectedMonster, setSelectedMonster] = useState<Monster | null>(null);
   const [attackType, setAttackType] = useState('melee');
   const [lastResult, setLastResult] = useState<CombatResult | null>(null);
+  const [lastMultiResult, setLastMultiResult] = useState<MultiCombatResult | null>(null);
+  const [cooldown, setCooldown] = useState(false);
 
   const { data: char } = useQuery({ queryKey: ['character'], queryFn: characterApi.me });
   const endurance = char?.enduranceCurrent ?? 0;
@@ -137,14 +172,28 @@ export function CombatPage() {
     queryFn: combatApi.history,
   });
 
+  const startCooldown = useCallback(() => {
+    setCooldown(true);
+    setTimeout(() => setCooldown(false), 1500);
+  }, []);
+
   const fight = useMutation({
-    mutationFn: () => combatApi.start(selectedMonster!.id, attackType),
+    mutationFn: (count: number = 1) => combatApi.start(selectedMonster!.id, attackType, count),
     onSuccess: (result) => {
-      setLastResult(result);
+      if (result.mode === 'multi') {
+        setLastMultiResult(result as MultiCombatResult);
+        setLastResult(null);
+      } else {
+        setLastResult(result as CombatResult);
+        setLastMultiResult(null);
+      }
       qc.invalidateQueries({ queryKey: ['character'] });
       qc.invalidateQueries({ queryKey: ['combatHistory'] });
       qc.invalidateQueries({ queryKey: ['questsActive'] });
+      qc.invalidateQueries({ queryKey: ['materialsInventory'] });
+      startCooldown();
     },
+    onError: () => startCooldown(),
   });
 
   if (isLoading) return <div style={{ padding: '2rem', color: '#6b7a99' }}>Chargement des monstres…</div>;
@@ -252,19 +301,26 @@ export function CombatPage() {
             {canFight && <span style={{ color: '#6b7a99' }}>({Math.floor(endurance / COMBAT_COST)} combats)</span>}
           </div>
 
-          {/* Bouton combattre */}
-          <button
-            className="btn btn-red"
-            style={{ width: '100%', fontSize: 15, padding: '0.75rem', opacity: canFight ? 1 : 0.5 }}
-            disabled={!selectedMonster || fight.isPending || !canFight}
-            onClick={() => fight.mutate()}
-          >
-            {fight.isPending ? (
-              <span><Swords size={14} style={{ display: 'inline', marginRight: 6 }} />Combat…</span>
-            ) : (
-              <span>⚔️ Combattre {selectedMonster ? `— ${selectedMonster.name}` : ''} ({COMBAT_COST}⚡)</span>
-            )}
-          </button>
+          {/* Boutons combattre */}
+          <div style={{ display: 'flex', gap: 6 }}>
+            {[1, 5, 10].map(n => (
+              <button
+                key={n}
+                className="btn btn-red"
+                style={{ flex: n === 1 ? 2 : 1, fontSize: n === 1 ? 14 : 12, padding: '0.75rem 0.5rem', opacity: canFight && !cooldown ? 1 : 0.5 }}
+                disabled={!selectedMonster || fight.isPending || !canFight || cooldown}
+                onClick={() => fight.mutate(n)}
+              >
+                {fight.isPending ? (
+                  <span><Swords size={14} style={{ display: 'inline', marginRight: 4 }} />Combat…</span>
+                ) : (
+                  n === 1
+                    ? <span>⚔️ Combat ({COMBAT_COST}⚡)</span>
+                    : <span>×{n} ({COMBAT_COST * n}⚡)</span>
+                )}
+              </button>
+            ))}
+          </div>
 
           {fight.isError && (
             <p style={{ color: '#e84040', fontSize: 12, marginTop: 8 }}>{(fight.error as Error).message}</p>
@@ -285,6 +341,7 @@ export function CombatPage() {
       </div>
 
       {/* Résultat du dernier combat */}
+      {lastMultiResult && <MultiCombatView result={lastMultiResult} />}
       {lastResult && <CombatLogView result={lastResult} />}
     </div>
   );