- Remove runfusion.yml, add opencode.yml with web terminal config
- Update all references across codebase (tests, docs, specs)
- Add OpenCode container setup with port 3000 and health checks
- Add ToolManifest Pydantic models with validators for ports, mounts, health checks, and traefik config
- Implement in-memory ToolRegistry with YAML loading and built-in manifest scanning
- Add FastAPI CRUD routes for listing, retrieving, and creating tool manifests
- Include built-in manifests for runfusion and code-server
- Harden web Dockerfile with unprivileged nginx and port 8080
- Add tool manifest specification documentation and architecture updates
Fusion-Task-Id: FN-003