feat(01-01): add Athena council type and schema contracts

- Add Athena council config interfaces and execution status types

- Add standalone Zod schemas for council member, council, and top-level Athena config

- Enforce 2-member minimum and bounded optional temperature validation

src/agents/athena/types.ts

@@ -0,0 +1,19 @@
+export interface CouncilMemberConfig {
+  model: string
+  temperature?: number
+  variant?: string
+  name?: string
+}
+
+export interface CouncilConfig {
+  members: CouncilMemberConfig[]
+}
+
+export interface AthenaConfig {
+  model?: string
+  council: CouncilConfig
+}
+
+export type CouncilMemberStatus = "completed" | "timeout" | "error"
+
+export type AgreementLevel = "unanimous" | "majority" | "minority" | "solo"