Add Home Manager module for `aichat` CLI, integrating Moonshot/Kimi API. Uses sops-nix for API key management. Add `spotify-mcp-server` as a system service, integrated with Hermes. Manages Spotify credentials via sops-nix. Enable `nextcloud` OIDC app. Configure `nextcloud-mcp` to restart on sops secret changes. Enable `zitadel` service.