Refactor NodeCG runtime preparation and update handling

- Updated paths and configurations in doctor.mjs and prepare-nodecg-runtime.mjs to use new build-config.mjs imports.
- Enhanced runtime installation checks and permissions validation.
- Introduced new update configuration management in update-config.ts, including loading and validating update settings.
- Implemented update service for managing update checks and downloads in update-service.ts.
- Replaced update-utils.ts with update-schema.ts for better structure and clarity in update handling.
- Added comprehensive tests for update download and settings management.
- Ensured secure handling of download URLs and improved error handling in update processes.

src/tests/update-download.test.ts

@@ -0,0 +1,58 @@
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import test from "node:test";
+
+import { downloadInstaller } from "../main/updates/update-download";
+
+test("downloadInstaller writes into the update temp directory and removes staging files", async () => {
+  const previousFetch = globalThis.fetch;
+  const tempDirectory = fs.mkdtempSync(path.join(os.tmpdir(), "scoreko-update-download-"));
+
+  globalThis.fetch = async () => new Response("installer-bytes");
+
+  try {
+    const installerPath = await downloadInstaller(
+      {
+        version: "0.2.0",
+        title: "Scoreko 0.2.0",
+        installer: {
+          name: "Scoreko/setup:0.2.0.exe",
+          downloadUrl: "https://updates.local/Scoreko-setup-0.2.0.exe",
+        },
+      },
+      { tempDirectory, allowInsecureHttp: false },
+    );
+
+    const downloadDirectory = path.join(tempDirectory, "scoreko-updates");
+    assert.equal(installerPath, path.join(downloadDirectory, "Scoreko_setup_0.2.0.exe"));
+    assert.equal(fs.readFileSync(installerPath, "utf8"), "installer-bytes");
+    assert.deepEqual(
+      fs.readdirSync(downloadDirectory).filter((entry) => entry.endsWith(".download")),
+      [],
+    );
+  } finally {
+    globalThis.fetch = previousFetch;
+  }
+});
+
+test("downloadInstaller rejects insecure production download URLs", async () => {
+  const tempDirectory = fs.mkdtempSync(path.join(os.tmpdir(), "scoreko-update-download-"));
+
+  await assert.rejects(
+    () =>
+      downloadInstaller(
+        {
+          version: "0.2.0",
+          title: "Scoreko 0.2.0",
+          installer: {
+            name: "Scoreko-setup-0.2.0.exe",
+            downloadUrl: "http://updates.local/Scoreko-setup-0.2.0.exe",
+          },
+        },
+        { tempDirectory, allowInsecureHttp: false },
+      ),
+    /unsupported protocol/,
+  );
+});