Unified overrides for custom router and orchestrator models (#820)

* support configurable orchestrator model via orchestration config section

* add self-hosting docs and demo for Plano-Orchestrator

* list all Plano-Orchestrator model variants in docs

* use overrides for custom routing and orchestration model

* update docs

* update orchestrator model name

* rename arch provider to plano, use llm_routing_model and agent_orchestration_model

* regenerate rendered config reference

crates/brightstaff/src/handlers/agent_selector.rs

@@ -178,6 +178,7 @@ mod tests {
         Arc::new(OrchestratorService::new(
             "http://localhost:8080".to_string(),
             "test-model".to_string(),
+            "plano-orchestrator".to_string(),
         ))
     }
 

crates/brightstaff/src/handlers/integration_tests.rs

@@ -23,6 +23,7 @@ mod tests {
         Arc::new(OrchestratorService::new(
             "http://localhost:8080".to_string(),
             "test-model".to_string(),
+            "plano-orchestrator".to_string(),
         ))
     }