Replace RouterService/RouterModelV1 (arch-router prompt) with
OrchestratorService/OrchestratorModelV1 (plano-orchestrator prompt)
for LLM routing. This ensures the correct system prompt is used when
llm_routing_model points at a Plano-Orchestrator model.
- Extend OrchestratorService with session caching, ModelMetricsService,
top-level routing preferences, and determine_route() for LLM routing
- Delete RouterService, RouterModel trait, RouterModelV1, and
ARCH_ROUTER_V1_SYSTEM_PROMPT
- Unify defaults to Plano-Orchestrator / plano-orchestrator
- Update CLI config generator, demos, docs, and config schema
Made-with: Cursor
