feat: attach desktop file paths as editable learner chips

electron/preload.cjs

@@ -29,7 +29,7 @@
  *
  * Channel names are mirrored in electron/main.cjs — keep them in sync.
  */
-const { contextBridge, ipcRenderer } = require("electron");
+const { contextBridge, ipcRenderer, webUtils } = require("electron");
 
 let openSettingsListener = null;
 let pendingOpenSettings = null;
@@ -40,6 +40,9 @@ ipcRenderer.on("lh:open-settings", (_event, section) => {
 
 contextBridge.exposeInMainWorld("lh", {
 	platform: process.platform,
+	// Resolve only a renderer-supplied, OS-backed File. No filesystem API,
+	// uploads, copies, or DOM File IPC to main; sandbox/isolation stay on.
+	getPathForFile: (file) => webUtils.getPathForFile(file),
 	...(process.argv?.includes("--lh-web-subscriptions") ? {
 		subscriptionTransport: "web",
 		openSubscriptionBrowser: (action) => ipcRenderer.invoke("lh:subscriptions:web-browser", action),