Example long-lived sidecar plugin (Rust half). Demonstrates the picoframe sidecar pattern: a persistent Bun HTTP server spawned once at startup, called over loopback with a shared-secret token, streaming progress to the UI as Tauri events.
The heavy lifting (spawn, handshake, health, SSE bridge, restart, kill-on-exit) lives in
[picoframe_core::sidecar]; this crate just configures it and exposes two commands.