feat: profile page character display, persistent auth, cleanup

- Large animated sprite on BotProfilePage with tier-aware rendering
- Dynamic status titles (UNSTOPPABLE, ON FIRE, FRESH MEAT, etc.)
- Nostr auth persisted to localStorage — survives navigation and HMR
- Remove grotesque close-up overlays (eyeballs, tongues, teeth, drool)
- Remove crowd cheering signs (too small to look good)
- Add archetype to bot stats API response
- SpritePreview now accepts tier prop

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

frontend/src/components/SpritePreview.vue

@@ -5,6 +5,7 @@ import { generateSpriteSheet, getBotColors, FRAME_SIZE, ANIMATIONS } from '../ga
 const props = defineProps<{
   seed: string
   archetype?: string
+  tier?: number
   size?: number
 }>()
 
@@ -36,7 +37,7 @@ function render() {
 
 function loadSprite() {
   const colors = getBotColors(props.seed)
-  const dataUrl = generateSpriteSheet(props.seed, 0, colors.primary, colors.secondary, props.archetype)
+  const dataUrl = generateSpriteSheet(props.seed, props.tier || 0, colors.primary, colors.secondary, props.archetype)
   img = new Image()
   img.onload = () => render()
   img.src = dataUrl