local dev setup + OPENAI_BASE_URL support + dashboard fix

- CLAUDE.md con arquitectura y comandos del proyecto
- env.example: agregar LIMIT_CONVERSATIONS, MAX_CHARS_PER_MESSAGE, OPENAI_BASE_URL
- docker-compose.override: puerto 3001, extra_hosts para modelo local en Linux
- OpenAI clients: soporte OPENAI_BASE_URL para apuntar a modelo local compatible
- stats.js: sync de órdenes en background, dashboard no bloquea al cargar
- package-lock: dbmate movido a prod dependencies

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

src/modules/3-turn-engine/nlu/specialists/browse.js

@@ -14,7 +14,8 @@ function getClient() {
     throw new Error("OPENAI_API_KEY is not set");
   }
   if (!_client) {
-    _client = new OpenAI({ apiKey });
+    const baseURL = process.env.OPENAI_BASE_URL || undefined;
+    _client = new OpenAI({ apiKey, ...(baseURL ? { baseURL } : {}) });
   }
   return _client;
 }