feat: enhance inspector and settings UI with new components and styles

- Added inspector panel for timeline and selection with corresponding sections.
- Updated settings tab structure to include MIDI, Audio, Art-Net, sACN, OSC, MQTT, Serial, Modbus TCP, Modbus RTU, and KNX configurations.
- Improved layout and styles for better responsiveness and usability.
- Introduced new CSS classes for truncating text and managing overflow.
- Adjusted grid layouts for app shell and inspector to accommodate new elements.

main.js

@@ -77,6 +77,47 @@ ipcMain.handle("audio:pickFile", async () => {
   };
 });
 
+ipcMain.handle("app:getUserDataPath", () => {
+  return app.getPath("userData");
+});
+
+ipcMain.handle("mappingLibrary:pickLoadFile", async (_event, payload) => {
+  const result = await dialog.showOpenDialog({
+    properties: ["openFile"],
+    defaultPath: payload?.defaultPath || "time4midi-mappings.json",
+    filters: [
+      { name: "Time4Midi Mapping", extensions: ["json"] }
+    ]
+  });
+
+  if (result.canceled || result.filePaths.length === 0) {
+    return { canceled: true };
+  }
+
+  return {
+    canceled: false,
+    filePath: result.filePaths[0]
+  };
+});
+
+ipcMain.handle("mappingLibrary:pickSaveFile", async (_event, payload) => {
+  const result = await dialog.showSaveDialog({
+    defaultPath: payload?.defaultPath || "time4midi-mappings.json",
+    filters: [
+      { name: "Time4Midi Mapping", extensions: ["json"] }
+    ]
+  });
+
+  if (result.canceled || !result.filePath) {
+    return { canceled: true };
+  }
+
+  return {
+    canceled: false,
+    filePath: result.filePath
+  };
+});
+
 app.whenReady().then(() => {
   createWindow();