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>

admin.tsx

@@ -133,7 +133,7 @@ function App() {
       const blob = await response.blob();
       const disposition = response.headers.get("content-disposition") ?? "";
       const fileNameMatch = disposition.match(/filename="([^"]+)"/i);
-      const fileName = fileNameMatch?.[1] ?? `quipslop-export-${Date.now()}.json`;
+      const fileName = fileNameMatch?.[1] ?? `argumentes-export-${Date.now()}.json`;
 
       const url = URL.createObjectURL(blob);
       const anchor = document.createElement("a");