- Add BUILD_AGENT_PROMPT_EXTENSION for orchestrator-focused main agent behavior
- Introduce OverridableAgentName type to allow build agent customization
- Update config schema to support build agent override in oh-my-opencode.json
- Inject orchestration prompt into build agent's system prompt
🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)