fix: fight restart bug, mobile TTS, character sizing, bitcoin symbols

- Fix fight replay showing empty scene: validate rounds before playing,
  retry loading fight data up to 5 times when rounds are missing
- Add COOP/COEP headers to production server for SharedArrayBuffer
  (required by Kokoro TTS WASM threading on mobile)
- Add blob: to scriptSrc/workerSrc CSP for Web Worker support
- Fix mobile character cutoff: raise ground line to 0.82, add
  MOBILE_SCALE_CAP (0.55) so fighters never shrink too small
- Add ₿ bitcoin chest badge to all fighter sprites (scales with tier)
- Add sats coin stack on bot profile page proportional to satsWon
- Seed dev tournament with 8 mock bots on startup (dev mode only)

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

server/src/engine/challenges-extra.ts

@@ -463,6 +463,14 @@ export const EXTRA_PROMPTS: Record<string, PromptEntry[]> = {
     { prompt: 'Roast someone who trusts custodial exchanges with their Bitcoin.' , theme: 'bitcoin' },
     { prompt: 'Roast someone who calls themselves a "Web3 developer" but can\'t deploy a smart contract.' , theme: 'bot_coding' },
     { prompt: 'Roast a sysadmin who uses root for everything.' , theme: 'bot_coding' },
+    { prompt: 'Roast a "vibe coder" who writes entire apps with AI prompts and has no idea how any of it works. 3 sentences.', theme: 'bot_coding' },
+    { prompt: 'Roast someone who replaced their entire engineering team with ChatGPT and wonders why production is on fire. 3 sentences.', theme: 'bot_coding' },
+    { prompt: 'Roast a developer who says "just use AI" instead of learning to code. 3 sentences.', theme: 'bot_coding' },
+    { prompt: 'Roast someone whose entire GitHub profile is AI-generated code they don\'t understand. 3 sentences.', theme: 'bot_coding' },
+    { prompt: 'Roast a startup founder who pivoted to AI 6 times in one year. 3 sentences.', theme: 'bot_coding' },
+    { prompt: 'Roast someone who uses 4 different AI coding assistants simultaneously and still can\'t ship. 3 sentences.', theme: 'bot_coding' },
+    { prompt: 'Roast a developer who added Rust to a JavaScript project "for performance" and now nobody can build it. 3 sentences.', theme: 'bot_coding' },
+    { prompt: 'Roast someone who says "I don\'t need tests, I have AI to find my bugs." 3 sentences.', theme: 'bot_coding' },
   ],
 
   creative_writing: [