fix(athena): address 6 council review findings — launcher, schema, filtering, presentation

- Forward temperature and permission through council-launcher to background manager
- Add LaunchInput.temperature and LaunchInput.permission to background-agent types
- Extract session guard with 5-minute timeout to prevent stale council locks
- Make council optional in AthenaOverrideConfigSchema for partial user overrides
- Support member lookup by both name and model ID in filterCouncilMembers
- Add provider/model-id format validation to CouncilMemberSchema
- Fix findings-presenter group header to show finding count instead of first finding's reporter count

src/tools/athena-council/council-launcher.ts

@@ -12,6 +12,8 @@ export function createCouncilLauncher(manager: BackgroundManager): CouncilLaunch
         parentMessageID: input.parentMessageID,
         parentAgent: input.parentAgent,
         model: input.model,
+        temperature: input.temperature,
+        permission: input.permission,
       })
     },
   }