add gui

gui/README.md

@@ -0,0 +1,36 @@
+# sjnmusic-gui
+
+Electron-based remote control for `sjnmusicd`. Pure HTTP client — the daemon
+owns the audio engine, this GUI just renders state and fires commands.
+
+## Run from source
+
+```bash
+cd gui
+npm install
+npm start
+```
+
+## Build distributables (Linux)
+
+```bash
+npm install
+npm run build:linux   # AppImage + .deb in gui/out/
+```
+
+## Architecture
+
+```
+gui/src/
+  main/         Electron main process (BrowserWindow, polling, tray)
+  preload/      contextBridge IPC → window.api.{get,post,patch,put,del,onTick}
+  renderer/     Web Components (no framework, hand-rolled CSS)
+```
+
+The daemon stays untouched; the only additions are:
+- `YtCandidate.thumbnail: Option<String>` (for picker cover art),
+- `daemon/src/mpris.rs` registering `org.mpris.MediaPlayer2.sjnmusic` on the
+  session bus so media keys work without the GUI open.
+
+State is polled from the main process at 1 Hz and pushed into the renderer
+via `webContents.send('tick', …)`.