feat: production hardening — background fights, queue tuning, CORS, cycling taglines

- Background fight loop: mock bots auto-fight every ~45s for site activity
  - Quiet hours (2-8 UTC) run 4x slower, jitter prevents robotic timing
  - Configurable via FIGHT_LOOP_ENABLED, FIGHT_LOOP_INTERVAL_MS
- Queue timeout: 30s in prod (was 3s), configurable via QUEUE_TIMEOUT_MS
- CORS: env-configurable via CORS_ORIGIN (default '*')
- Homepage: 40 cycling taglines with typewriter effect
- docker-compose: document all new env vars

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

server/src/index.ts

@@ -2,6 +2,7 @@ import { serve } from '@hono/node-server'
 import { app } from './app.js'
 import { runMigrations } from './db/startup.js'
 import { seedMockBots } from './engine/mock.js'
+import { startBackgroundFights } from './engine/background.js'
 
 // Run migrations and seed mock bots before starting the server
 runMigrations()
@@ -11,4 +12,7 @@ const port = Number(process.env.PORT) || 9100
 
 serve({ fetch: app.fetch, port }, () => {
   console.log(`[botfights] server listening on http://localhost:${port}`)
+
+  // Start background fight loop so the site always has fresh activity
+  startBackgroundFights()
 })