fix: preserve Windows data during upgrades

packages/app-tests/windowsInstallerConfig.test.ts

@@ -0,0 +1,23 @@
+import { existsSync, readFileSync } from "node:fs";
+import { strict as assert } from "node:assert";
+import { join } from "node:path";
+import test from "node:test";
+
+const tauriConfig = JSON.parse(readFileSync("src-tauri/tauri.conf.json", "utf8")) as {
+  bundle?: { windows?: { nsis?: { installMode?: string; template?: string } } };
+};
+const nsisTemplate = readFileSync("src-tauri/windows/nsis/installer.nsi", "utf8");
+
+test("Windows NSIS installer template is tracked by config", () => {
+  const nsis = tauriConfig.bundle?.windows?.nsis;
+
+  assert.equal(nsis?.installMode, "currentUser");
+  assert.equal(nsis?.template, "windows/nsis/installer.nsi");
+  assert.equal(existsSync(join("src-tauri", nsis.template)), true);
+});
+
+test("Windows upgrades preserve user data when reinstalling", () => {
+  assert.match(nsisTemplate, /\$\{OrIf\} \$R0 = 1/);
+  assert.match(nsisTemplate, /StrCpy \$R1 "\$R1 \/UPDATE"/);
+  assert.match(nsisTemplate, /\$\{AndIf\} \$UpdateMode <> 1/);
+});