fix: Windows desktop updater — sign setup.exe, preserve latest.json on deploy

Sign *-setup.exe for updater manifest, pick newest bundle per platform,
reconcile after git checkout, and stop overwriting latest.json with empty
placeholder. Bump desktop to 0.1.3.

Co-authored-by: Cursor <cursoragent@cursor.com>

desktop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@goldenchart/desktop",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "private": true,
   "type": "module",
   "scripts": {

desktop/src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "GoldenChart",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "identifier": "com.goldenchart.desktop",
   "build": {
     "beforeDevCommand": "npm run dev",