feat: convert to argument.es — Spanish, vote buttons, Docker

- Translate all ~430 prompts to Spanish with cultural adaptations
- Translate all UI strings (frontend, admin, history, broadcast)
- Translate AI system prompts; models now respond in Spanish
- Replace Twitch/Fossabot viewer voting with in-site vote buttons
- Add POST /api/vote endpoint (IP-based, supports vote switching)
- Vote buttons appear during voting phase with active state highlight
- Rename project to argument.es throughout (package.json, cookie, DB)
- Add docker-compose.yml with SQLite volume mount
- Add .env.sample documenting all required and optional vars

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

broadcast.ts

@@ -291,7 +291,7 @@ function drawHeader() {
 
   ctx.font = '700 40px "Inter", sans-serif';
   ctx.fillStyle = "#ededed";
-  ctx.fillText("quipslop", 48, 76);
+  ctx.fillText("argument.es", 48, 76);
 
 }