desktop: revert screenshare to video-only capture

The 1.0.1 loopback-audio request broke Windows screenshare entirely;
we don't need Windows audio, so go back to plain {video}.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/desktop/src/ipc.ts

@@ -145,15 +145,7 @@ ipcMain.on("ipcCall", async function (_ev: IpcMainEvent, payload) {
             }));
             break;
         case "callDisplayMediaCallback":
-            // Blap: capture system audio alongside the shared screen. Electron's
-            // "loopback" audio is supported on Windows and macOS only (not Linux), so we
-            // gate on platform — passing it on Linux would fail the whole share.
-            await getDisplayMediaCallback()?.({
-                video: args[0],
-                ...(process.platform === "win32" || process.platform === "darwin"
-                    ? { audio: "loopback" as const }
-                    : {}),
-            });
+            await getDisplayMediaCallback()?.({ video: args[0] });
             setDisplayMediaCallback(null);
             ret = null;
             break;