feat: Windows NSIS installer, embedded icons, GUI auto-launch backend

- Add package/installer.nsi (Full/Server/Client) and toolchain.nsi
- Embed icon.ico (rounded corners) into homed.exe/waiter.exe via .syso
- GUI auto-launches homed.exe from parent dir (Windows only)
- GUI fallback connections.json from app resource dir
- Add initconfig command for config.db seeding
- Replace waiter rawmode* with raw_{unix,windows,other}.go
- Fix .gitignore: /homed instead of homed, add login.json
- Update icon.svg with rounded rect, new mascot.svg

cmd/gui/package.json

@@ -13,7 +13,9 @@
   "devDependencies": {
     "asar": "^3.2.0",
     "electron-builder": "^26.15.3",
-    "electron-packager": "^17.1.2"
+    "electron-packager": "^17.1.2",
+    "icojs": "^0.23.0",
+    "sharp": "^0.35.3"
   },
   "build": {
     "appId": "com.homeagent.gui",