feat: node info, build info and acrylic web theme

Squash of recent dev work: return_session login, backend switcher, line
detail timeline, overview strips, node platform/country/ISP info with flags
and icons, build info (version, tag, time) behind site.show_build, and the
acrylic display theme.

web/dev.mjs

@@ -1,7 +1,50 @@
-// 同时启动展示端（5173）和管理端（5174/admin/）；Ctrl+C 一起退出。
+// 同时启动展示端（5173）和管理端（5175，经展示端的 /admin/ 访问）；Ctrl+C 一起退出。
+// 不经过 shell：直接用 node 跑各自目录下的 vite，输出带前缀，端口被占时直接报错。
 import { spawn } from 'node:child_process'
+import { fileURLToPath } from 'node:url'
 
-const children = ['display', 'admin'].map((name) => spawn('npm', ['run', 'dev', '-w', name], { stdio: 'inherit', shell: true }))
-const stop = () => children.forEach((c) => c.kill())
+const vite = fileURLToPath(new URL('./node_modules/vite/bin/vite.js', import.meta.url))
+
+// 颜色：和 Vite 自己的输出一致（绿色的 ➜、青色/蓝色的链接）；设了 NO_COLOR 就不上色
+const color = !process.env.NO_COLOR
+const paint = (code, text) => (color ? `[${code}m${text}` : text)
+const bold = (t) => paint('1', t)
+const dim = (t) => paint('2', t)
+const green = (t) => paint('32', t)
+const cyan = (t) => paint('36', t)
+const magenta = (t) => paint('35', t)
+const link = (url) => paint('36;4', url)
+
+const apps = [
+  { name: 'display', tint: cyan, cwd: fileURLToPath(new URL('./display/', import.meta.url)) },
+  { name: 'admin  ', tint: magenta, cwd: fileURLToPath(new URL('./admin/', import.meta.url)) },
+]
+
+console.log('')
+console.log(`  ${green('➜')}  ${bold('展示端')}  ${link('http://localhost:5173/')}`)
+console.log(`  ${green('➜')}  ${bold('管理端')}  ${link('http://localhost:5173/admin/')}  ${dim('（也可以直接开 http://localhost:5175/admin/）')}`)
+console.log('')
+
+const children = apps.map(({ name, tint, cwd }) => {
+  const child = spawn(process.execPath, [vite], { cwd, stdio: ['inherit', 'pipe', 'pipe'], env: { ...process.env, ...(color ? { FORCE_COLOR: '1' } : {}) } })
+  const prefix = (stream, out) =>
+    stream.on('data', (chunk) => {
+      for (const line of String(chunk).split(/\r?\n/)) if (line.trim()) out.write(`${tint(`[${name}]`)} ${line}\n`)
+    })
+  prefix(child.stdout, process.stdout)
+  prefix(child.stderr, process.stderr)
+  child.on('exit', (code) => {
+    if (code) {
+      console.error(`${tint(`[${name}]`)} ${paint('31', `退出了（${code}），一起停掉`)}`)
+      stop()
+      process.exitCode = code
+    }
+  })
+  return child
+})
+
+function stop() {
+  for (const c of children) c.kill()
+}
 process.on('SIGINT', stop)
 process.on('exit', stop)