refactor(athena): remove type assertions and improve agent factories

- Replace 'as AgentConfig' casts with proper typing in agent.ts and council-member-agent.ts
- Extract permission into typed variable following Sisyphus pattern
- Add GPT/non-GPT model branching to council-member-agent
- Use parseModelString for schema validation instead of inline logic
- Add strict() to council and athena config schemas
- Fix athena restriction list (remove redundant athena_council deny)
- Add orchestrator logging for council execution
- Update system prompt to notification-based workflow

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

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

src/config/schema/athena.ts

@@ -1,14 +1,12 @@
 import { z } from "zod"
+import { parseModelString } from "../../agents/athena/model-parser"
 
 /** Validates model string format: "provider/model-id" (e.g., "openai/gpt-5.3-codex"). */
 const ModelStringSchema = z
   .string()
   .min(1)
   .refine(
-    (model) => {
-      const slashIndex = model.indexOf("/")
-      return slashIndex > 0 && slashIndex < model.length - 1
-    },
+    (model) => parseModelString(model) !== null,
     { message: 'Model must be in "provider/model-id" format (e.g., "openai/gpt-5.3-codex")' }
   )
 
@@ -20,9 +18,9 @@ export const CouncilMemberSchema = z.object({
 
 export const CouncilConfigSchema = z.object({
   members: z.array(CouncilMemberSchema).min(2),
-})
+}).strict()
 
 export const AthenaConfigSchema = z.object({
   model: z.string().optional(),
   council: CouncilConfigSchema,
-})
+}).strict()