refactor(athena): remove dead council types and stale barrel exports

Remove CouncilLaunchFailure, CouncilLaunchedMember, CouncilLaunchResult types and barrel exports for deleted council-orchestrator and council-prompt modules.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/agents/athena/index.ts

@@ -2,6 +2,4 @@ export * from "./types"
 export * from "./agent"
 export * from "./council-member-agent"
 export * from "./model-parser"
-export * from "./council-prompt"
-export * from "./council-orchestrator"