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/start.sh

@@ -1,12 +1,12 @@
 #!/usr/bin/env bash
 # 卫戍协议：盟约 · macOS / Linux start script. Docs: docs/DEPLOY.md
 #   scripts/start.sh [--port 3001] [--no-open] [--no-local] [--no-assets] …   (arguments go to scripts/launch.mjs)
-# Checks Node.js ≥ 18, runs `npm ci` on the first run, then scripts/launch.mjs (tools/setup.mjs → server → browser).
+# Checks Node.js ≥ 22, runs `npm ci` on the first run, then scripts/launch.mjs (tools/setup.mjs → server → browser).
 set -euo pipefail
 cd "$(dirname "$0")/.."
 
 if ! command -v node >/dev/null 2>&1; then
-  echo "未找到 Node.js（需要 18 或更高，推荐 22 LTS）。Node.js not found."
+  echo "未找到 Node.js（需要 22 或更高，22 / 24 LTS）。Node.js not found."
   if [ "$(uname -s)" = "Darwin" ]; then
     echo "  安装：brew install node@22   或   https://nodejs.org/zh-cn/download"
   else
@@ -14,8 +14,8 @@ if ! command -v node >/dev/null 2>&1; then
   fi
   exit 1
 fi
-if ! node -e "process.exit(Number(process.versions.node.split('.')[0])>=18?0:1)"; then
-  echo "Node.js $(node -v) 太旧，需要 18 或更高（推荐 22 LTS）：https://nodejs.org/zh-cn/download"
+if ! node -e "process.exit(Number(process.versions.node.split('.')[0])>=22?0:1)"; then
+  echo "Node.js $(node -v) 太旧，需要 22 或更高（22 / 24 LTS）：https://nodejs.org/zh-cn/download"
   exit 1
 fi