feat: move creator pubkey to env, fix mobile TTS + signer, button loaders

Security:
- Move CREATOR_PUBKEY from hardcoded constant to BOTFIGHTS_CREATOR_PUBKEYS
  env var. Shared isCreatorPubkey() in constants.ts used by auth, admin,
  tournaments. Frontend checks authorization via API, not client-side.

Mobile fixes:
- Nostr signer: poll for window.nostr up to 3s (Amber injects late).
- TTS: auto-unlock AudioContext on first user interaction via
  installAutoUnlock() on fight page mount.

UX:
- Add loading spinners to "I BUILD BOTS" and "I FIGHT MYSELF" buttons.

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

frontend/src/pages/AdminPage.vue

@@ -1,10 +1,8 @@
 <script setup lang="ts">
-import { ref, onMounted, onUnmounted, computed } from 'vue'
+import { ref, onMounted, onUnmounted } from 'vue'
 import { useRouter } from 'vue-router'
 import { useNostr } from '../composables/useNostr'
 
-const CREATOR_PUBKEY = 'da5e0c1b646bdb13c2300f805b0ca3e5afe5b052c594ce78bac8978d21c3fa39'
-
 interface Stats {
   uptime: number
   rssBytes: number
@@ -51,7 +49,7 @@ interface Fight {
 const { pubkey } = useNostr()
 const router = useRouter()
 
-const isAuthorized = computed(() => pubkey.value === CREATOR_PUBKEY)
+const isAuthorized = ref(false)
 const stats = ref<Stats | null>(null)
 const bots = ref<Bot[]>([])
 const fights = ref<Fight[]>([])
@@ -119,11 +117,15 @@ function botName(id: string): string {
 }
 
 onMounted(async () => {
-  if (!isAuthorized.value) {
-    router.replace('/')
-    return
-  }
-  await Promise.all([fetchStats(), fetchBots(), fetchFights()])
+  if (!pubkey.value) { router.replace('/'); return }
+  // Check authorization via API — no hardcoded pubkeys in frontend
+  try {
+    const res = await fetch('/api/admin/stats', { headers: headers() })
+    if (!res.ok) { router.replace('/'); return }
+    stats.value = await res.json()
+    isAuthorized.value = true
+  } catch { router.replace('/'); return }
+  await Promise.all([fetchBots(), fetchFights()])
   isLoading.value = false
   refreshTimer = setInterval(fetchStats, 15_000)
 })

frontend/src/pages/FightPage.vue

@@ -156,7 +156,13 @@ async function initLiveScene() {
       liveScene.startMusic()
     }
     announceDeepIntro()
-    await liveScene.playEntrance()
+    try {
+      await liveScene.playEntrance()
+    } catch (err) {
+      console.warn('[FightPage] entrance failed:', err)
+    }
+    // Safety: ensure fighters are visible after entrance (prevents invisible characters on mobile)
+    liveScene._resetPositions()
   }
 
   liveLogItems.value.push(