feat(org): add LiteLLM usage stats to organization dashboard

Replace mock token usage with real data from LiteLLM free-tier APIs
(global/activity, global/activity/model, global/spend/models). Adds
per-model breakdown table, loading/error states, usage data models
with serde tests, and i18n keys for all five languages.

Also includes: replace Ollama with LiteLLM proxy, update config,
docker-compose, and provider infrastructure.

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

assets/i18n/pt.json

@@ -144,6 +144,16 @@
     "email_address": "Endereco de Email",
     "email_placeholder": "colleague@company.com",
     "send_invite": "Enviar Convite",
+    "total_spend": "Gasto total",
+    "total_tokens": "Tokens totais",
+    "model_usage": "Uso por modelo",
+    "model": "Modelo",
+    "tokens": "Tokens",
+    "spend": "Gasto",
+    "usage_unavailable": "Dados de uso indisponiveis",
+    "loading_usage": "Carregando dados de uso...",
+    "prompt_tokens": "Tokens de entrada",
+    "completion_tokens": "Tokens de resposta",
     "pricing_title": "Precos",
     "pricing_subtitle": "Escolha o plano adequado a sua organizacao"
   },