fix: add DPI awareness to NSIS installer

Add ManifestDPIAware true via a custom NSIS include file so the
installer renders at native resolution on high-DPI displays.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

assets/installer.nsh

@@ -0,0 +1 @@
+ManifestDPIAware true

package.json

@@ -126,6 +126,7 @@
       "oneClick": false,
       "perMachine": false,
       "allowToChangeInstallationDirectory": true,
+      "include": "assets/installer.nsh",
       "installerIcon": "assets/icons/windows/icon.ico",
       "uninstallerIcon": "assets/icons/windows/icon.ico"
     },