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>

.env.sample

@@ -0,0 +1,28 @@
+# ── Required ──────────────────────────────────────────────────────────────────
+
+# OpenRouter API key — get one at https://openrouter.ai/keys
+OPENROUTER_API_KEY=sk-or-v1-...
+
+# Admin panel password (choose something strong)
+ADMIN_SECRET=change-me-please
+
+# ── Optional ──────────────────────────────────────────────────────────────────
+
+# Server port (default: 5109)
+PORT=5109
+
+# Path to the SQLite database file
+# When using Docker, this is handled via the volume mount (/data/argumentes.sqlite)
+DATABASE_PATH=argumentes.sqlite
+
+# Rate limits (requests per minute)
+HISTORY_LIMIT_PER_MIN=120
+ADMIN_LIMIT_PER_MIN=10
+
+# WebSocket limits
+MAX_WS_GLOBAL=100000
+MAX_WS_PER_IP=8
+MAX_WS_NEW_PER_SEC=50
+
+# Viewer vote broadcast debounce in ms (default: 250)
+VIEWER_VOTE_BROADCAST_DEBOUNCE_MS=250