feat: Add NSIS installer target and persistent SQLite storage

- Add NSIS installer as default target (--target nsis)
- Keep portable option available (--target portable)
- Store SQLite database in %APPDATA%\Meeting-Assistant for persistence
- Portable temp folder cleanup no longer affects SQLite data
- Update build-client.bat with --target parameter support
- Update DEPLOYMENT.md with new options and comparisons

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

client/package.json

@@ -46,13 +46,21 @@
     "win": {
       "target": [
         {
-          "target": "portable",
+          "target": "nsis",
           "arch": ["x64"]
         }
       ],
       "icon": "assets/icon.ico",
       "signAndEditExecutable": false
     },
+    "nsis": {
+      "oneClick": false,
+      "allowToChangeInstallationDirectory": true,
+      "artifactName": "${productName}-${version}-setup.${ext}",
+      "installerIcon": "assets/icon.ico",
+      "uninstallerIcon": "assets/icon.ico",
+      "deleteAppDataOnUninstall": false
+    },
     "mac": {
       "target": [
         {