Replace oracle as the agent for council background tasks with a purpose-built
council-member agent. This avoids coupling to oracle's config/prompt and provides
proper read-only tool restrictions (deny write, edit, task, athena_council).
- New council-member-agent.ts with analysis-oriented system prompt
- Registered in agentSources (hidden from Sisyphus delegation table)
- Added to type system, Zod schemas, display names, tool restrictions
- Minimal model fallback (always overridden per council member at launch)
- Council orchestrator now launches members as council-member agent
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Remove crash-causing name fields from 6 agent configs (sisyphus, hephaestus,
atlas, metis, momus, prometheus). The name field approach breaks opencode
because Agent.get(agent.name) uses name as lookup key.
Add getAgentConfigKey() to agent-display-names.ts for resolving display names
back to lowercase config keys (e.g. 'Atlas (Plan Executor)' -> 'atlas').
