frank-default-small: lower context by 32k per stream for cache headroom

3 slots x 229376 (262144 - 32768) = 688128 total context. Updates the
.env, models.json (contextWindow/maxTokens 229376 per slot), and the
index/deployment/ornith runbook references.

docs/LLM/index.md

@@ -20,7 +20,7 @@ graph LR
         B[upstream llama.cpp b10121
 frank-default-small, port 7770]
         C[Ornith-1.5-35B-A3B-CRACK Q8_0
-native MTP, MoE experts offloaded via override, 786432 ctx]
+native MTP, MoE experts offloaded via override, 688128 ctx]
         A --> B --> C
     end