feat: Nostr profile enrichment with caching

Fetch full kind:0 metadata (display_name, about, banner, nip05) from
relays with a 5-min TTL cache. Show Nostr banner, display name, and
NIP-05 on bot profile pages. Expose ownerPubkey in stats API.

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

frontend/src/pages/BotProfilePage.vue

@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import { ref, reactive, computed, onMounted, onUnmounted } from 'vue'
 import { useRoute, useRouter, RouterLink } from 'vue-router'
-import { useNostr } from '../composables/useNostr'
+import { useNostr, type NostrProfile } from '../composables/useNostr'
 import SpritePreview from '../components/SpritePreview.vue'
 import HumanPreview from '../components/HumanPreview.vue'
 import WalletConnect from '../components/WalletConnect.vue'
@@ -10,7 +10,7 @@ import type { SpriteCustomization } from '../game/sprites'
 
 const route = useRoute()
 const router = useRouter()
-const { bot: nostrBot, pubkey, isLoggedIn, logout, updateCustomization, updateWebhook } = useNostr()
+const { bot: nostrBot, pubkey, isLoggedIn, logout, updateCustomization, updateWebhook, fetchNostrProfile } = useNostr()
 const botName = route.params.name as string
 
 interface BotCustomization {
@@ -29,6 +29,7 @@ interface BotStats {
   archetype: string
   customization: BotCustomization | null
   profilePicUrl: string | null
+  ownerPubkey: string | null
   eloRating: number
   wins: number
   losses: number
@@ -86,6 +87,7 @@ const showChoose = ref(false)
 const waitingFighters = ref<QueueEntry[]>([])
 let pollHandle: ReturnType<typeof setInterval> | null = null
 
+const nostrProfile = ref<NostrProfile | null>(null)
 const loadError = ref('')
 const fightError = ref('')
 const showCustomize = ref(false)
@@ -276,6 +278,13 @@ onMounted(async () => {
   }
   isLoading.value = false
 
+  // Fetch Nostr profile for the bot owner (non-blocking)
+  if (stats.value?.ownerPubkey) {
+    fetchNostrProfile(stats.value.ownerPubkey).then(p => {
+      nostrProfile.value = p
+    }).catch(() => {})
+  }
+
   // Poll queue for "choose your fight"
   pollQueue()
   pollHandle = setInterval(pollQueue, 4000)
@@ -360,7 +369,14 @@ const tierClass = (t: number) => `tier-${t}`
 
           <!-- LEFT COLUMN: Character + Stats + Actions -->
           <div class="lg:w-[380px] lg:shrink-0 flex flex-col">
-            <div class="border border-border bg-surface-raised/30 p-6 overflow-hidden">
+            <!-- Nostr banner -->
+            <div v-if="nostrProfile?.banner" class="relative h-24 -mx-0 mb-0 overflow-hidden border border-border border-b-0">
+              <img :src="nostrProfile.banner" alt="" class="w-full h-full object-cover opacity-60" />
+              <div class="absolute inset-0 bg-gradient-to-t from-surface-base to-transparent" />
+            </div>
+
+            <div class="border border-border bg-surface-raised/30 p-6 overflow-hidden"
+                 :class="{ 'border-t-0': nostrProfile?.banner }">
               <!-- Human player: just the human avatar, centered -->
               <div v-if="stats.archetype === 'human'" class="flex justify-center mb-4">
                 <HumanPreview
@@ -409,6 +425,15 @@ const tierClass = (t: number) => `tier-${t}`
                 <p class="font-mono text-text-muted text-[10px] mt-0.5">
                   #{{ stats.rank }} of {{ stats.totalBots }}
                 </p>
+                <!-- Nostr identity -->
+                <div v-if="nostrProfile?.displayName || nostrProfile?.nip05" class="mt-2 space-y-0.5">
+                  <p v-if="nostrProfile.displayName" class="font-mono text-xs text-text-secondary">
+                    {{ nostrProfile.displayName }}
+                  </p>
+                  <p v-if="nostrProfile.nip05" class="font-mono text-[10px] text-neon-purple">
+                    {{ nostrProfile.nip05 }}
+                  </p>
+                </div>
                 <button
                   v-if="isOwner && stats.archetype !== 'human'"
                   class="mt-2 font-mono text-[10px] text-neon-cyan/60 hover:text-neon-cyan transition-colors"