chore: remove all Twitch/streaming references

- Remove Twitch link from standings sidebar
- Delete scripts/stream-browser.ts (Twitch streaming script)
- Remove start:stream and start:stream:dryrun npm scripts
- Fix quipslop-export filename fallback in admin.tsx
- Fix hardcoded quipslop.sqlite in check-db.ts
- Rewrite README.md in Spanish, no Twitch mentions

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

check-db.ts

@@ -1,4 +1,4 @@
 import { Database } from "bun:sqlite";
-const db = new Database("quipslop.sqlite");
+const db = new Database("argumentes.sqlite");
 const rows = db.query("SELECT id, num FROM rounds ORDER BY id DESC LIMIT 20").all();
 console.log(rows);