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/config/schema/athena.ts

@@ -0,0 +1,21 @@
+import { z } from "zod"
+
+export const CouncilMemberSchema = z.object({
+  model: z.string(),
+  temperature: z.number().min(0).max(2).optional(),
+  variant: z.string().optional(),
+  name: z.string().optional(),
+})
+
+export const CouncilConfigSchema = z.object({
+  members: z.array(CouncilMemberSchema).min(2),
+})
+
+export const AthenaConfigSchema = z.object({
+  model: z.string().optional(),
+  council: CouncilConfigSchema,
+})
+
+export type CouncilMemberSchemaType = z.infer<typeof CouncilMemberSchema>
+export type CouncilConfigSchemaType = z.infer<typeof CouncilConfigSchema>
+export type AthenaConfigSchemaType = z.infer<typeof AthenaConfigSchema>