fix ipc naming for get system platform (#140)

src/ipc/handlers/window_handlers.ts

@@ -49,5 +49,5 @@ export function registerWindowHandlers() {
   ipcMain.handle("window:minimize", handleMinimize);
   ipcMain.handle("window:maximize", handleMaximize);
   ipcMain.handle("window:close", handleClose);
-  ipcMain.handle("window:get-platform", handleGetSystemPlatform);
+  ipcMain.handle("get-system-platform", handleGetSystemPlatform);
 }

src/preload.ts

@@ -63,7 +63,7 @@ const validInvokeChannels = [
   "window:minimize",
   "window:maximize",
   "window:close",
-  "window:get-platform",
+  "get-system-platform",
   "upload-to-signed-url",
   "delete-chat",
   "delete-messages",