feat: zap the winner button with lightning animation

Add ZAP WINNER button in FightViewer after fight ends. Server endpoint
POST /api/payments/zap increments zapsReceived on winner bot. Show zap
count on bot profile page. Add zaps_received column with migration.

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

frontend/src/components/FightViewer.vue

@@ -9,6 +9,7 @@ import {
   setMusicIntensity, stopAllAudio,
   setMasterMute, isMasterMuted, ensureAudioContext,
   speakQuestion, speakAnswer, speakNarration,
+  prefetchQuestion, prefetchAnswer, prefetchNarration,
   sfxRandomComedy, sfxRandomFail, sfxVineBoom, sfxEmotionalDamage,
 } from '../game/sounds'
 
@@ -70,6 +71,28 @@ const glitching = ref(false)
 const soundOn = ref(true)
 const insanityMode = ref(false)
 
+// Zap the winner
+const zapSent = ref(false)
+const zapAnimating = ref(false)
+
+async function zapWinner() {
+  if (!props.fight.winnerId || zapSent.value || zapAnimating.value) return
+  zapAnimating.value = true
+  try {
+    const res = await fetch('/api/payments/zap', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        winnerId: props.fight.winnerId,
+        fightId: props.fight.id,
+        amountSats: 21,
+      }),
+    })
+    if (res.ok) zapSent.value = true
+  } catch { /* ignore */ }
+  setTimeout(() => { zapAnimating.value = false }, 800)
+}
+
 // Reactions
 const REACTION_EMOJIS: Record<string, string> = {
   fist: '\u{1F44A}',
@@ -758,6 +781,20 @@ async function _doReplay() {
         >
           {{ insanityMode ? 'INSANITY' : 'SKIP' }}
         </button>
+        <!-- Zap winner button -->
+        <button
+          v-if="fight.status === 'finished' && fight.winnerId && !isReplaying"
+          class="px-3 py-1.5 border font-display font-bold text-[10px] tracking-wider transition-all
+                 disabled:opacity-30 disabled:cursor-not-allowed"
+          :class="zapSent
+            ? 'border-neon-yellow/50 text-neon-yellow bg-neon-yellow/10'
+            : 'border-neon-yellow/30 text-neon-yellow hover:bg-neon-yellow/10 hover:border-neon-yellow/50'"
+          :disabled="zapSent || zapAnimating"
+          @click="zapWinner"
+        >
+          <span :class="{ 'zap-flash': zapAnimating }">{{ zapSent ? 'ZAPPED!' : 'ZAP WINNER' }}</span>
+        </button>
+
         <span class="font-pixel text-[10px] text-text-muted">{{ fight.status === 'finished' ? 'FINISHED' : fight.status.toUpperCase() }}</span>
       </div>
 
@@ -916,6 +953,18 @@ async function _doReplay() {
   100% { opacity: 0; transform: translateY(-140px) scale(0.6); }
 }
 
+/* Zap lightning flash */
+.zap-flash {
+  animation: zap-bolt 0.8s ease-out;
+}
+@keyframes zap-bolt {
+  0% { opacity: 1; filter: brightness(1); }
+  15% { opacity: 1; filter: brightness(3) drop-shadow(0 0 8px #ffe14d); }
+  30% { opacity: 0.6; filter: brightness(1.5); }
+  50% { opacity: 1; filter: brightness(2.5) drop-shadow(0 0 12px #ffe14d); }
+  100% { opacity: 1; filter: brightness(1); }
+}
+
 /* VHS scanline overlay on canvas */
 .glitch-container::after {
   content: '';