feat(desktop): upgrade Electron to 43.3 for Linux frameless rounded corners (#2765)

* feat(desktop): upgrade Electron to 43.3 for Linux frameless rounded corners

- electron ^41.2.1 -> ^43.3.0 (electron/electron#51459/#52111: rounded
  corners for frameless windows on Linux, default-on; disable via
  roundedCorners: false)
- @electron/rebuild ^3.7.0 -> ^4.2.0 to build native modules against
  the new Electron ABI
- pin node-abi to 4.33.0 via root overrides so @electron/rebuild (and
  electron-builder's internal rebuild) can resolve Electron 43's ABI
- README: Electron 43 ships its own fixed extractor (extract-zip 2.0.1
  Node-24 unpack bug no longer applies; ensure-electron remains a
  safety net for interrupted/wrong-arch installs)

* chore: re-trigger pr-review after adding visual evidence

* fix(desktop): scope node-abi to Electron rebuild tooling

* chore: re-trigger pr-review after dependency fix

* chore: re-trigger pr-review with drag evidence

* chore: retry pr-review after evidence confirmation

packages/electron/package.json

@@ -13,9 +13,10 @@
     "electron-updater": "^6.8.3"
   },
   "devDependencies": {
-    "@electron/rebuild": "^3.7.0",
-    "electron": "^41.2.1",
-    "electron-builder": "^26.0.0"
+    "@electron/rebuild": "^4.2.0",
+    "electron": "^43.3.0",
+    "electron-builder": "^26.0.0",
+    "node-abi": "^4.33.0"
   },
   "trustedDependencies": [
     "electron"