Node 22+ everywhere, LF text on Windows checkouts, CI actions v7

- Node minimum is 22 in package.json engines, the start scripts, the service installer, setup and doctor,
  matching the README, the release notes and the CI matrix (22 / 24).
- .gitattributes: CSS, HTML, JSON, Markdown and YAML check out with LF, so `node --test` on Windows matches the
  CSS rules the UI tests read; the Windows test step is no longer continue-on-error.
- CI: actions/checkout@v7 and actions/setup-node@v7 (Node 24 runtime).

scripts/launch.mjs

@@ -20,8 +20,8 @@ import fs from 'node:fs';
 const ROOT = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
 const IS_WIN = process.platform === 'win32';
 
-if (Number(process.versions.node.split('.')[0]) < 18) {
-  console.error(`Node.js ${process.versions.node} 太旧，需要 18 或更高（推荐 22 LTS）：https://nodejs.org/zh-cn/download`);
+if (Number(process.versions.node.split('.')[0]) < 22) {
+  console.error(`Node.js ${process.versions.node} 太旧，需要 22 或更高（22 / 24 LTS）：https://nodejs.org/zh-cn/download`);
   process.exit(1);
 }