feat: DSH 悬浮窗 v0.1.0 — 原生置顶小窗 + 会话镜像 + 抓屏隐身

- shell: WinForms + WebView2 原生壳（无边框/置顶/固定位置/锁定尺寸/全屏/自适应缩放/截图排除）
- shell/ui.html: 自适应界面（工具栏、会话镜像区、底部聊天框、轮/步/tok/s/MTOK/缓存命中/上下文状态条、外观设置）
- lib/host.js: DSH 插件 Host 半（endpoint 写入、SSE 会话与指标快照、float_window Agent 工具）
- tools: WebView2 SDK 拉取、BOM 修复、Host 冒烟测试
- README: 架构、实测结论（WDA_EXCLUDEFROMCAPTURE、玻璃模式、DPI、WebView2 加载）

tools/smoke-host.mjs

@@ -0,0 +1,51 @@
+/**
+ * 冒烟测试：用假的 ctx 调 apply()，确认插件不会抛异常，路由能应答。
+ * 用法：node tools/smoke-host.mjs
+ */
+import { apply, name, inject } from '../lib/host.js'
+
+const routes = []
+const events = []
+const effects = []
+
+const ctx = {
+  logger: { info: (...a) => console.log('[mock]', ...a) },
+  webServer: {
+    port: 3099,
+    host: '127.0.0.1',
+    register: (r) => { routes.push(r); return () => { } },
+  },
+  get: () => undefined,
+  set: () => { },
+  on: (ev, fn) => { events.push([ev, fn]); return () => { } },
+  effect: (fn) => { const d = fn(); effects.push(d); return () => { } },
+}
+
+console.log('name =', name, '| inject =', JSON.stringify(inject))
+apply(ctx)
+console.log('routes =', routes.map((r) => `${r.kind}:${r.path}`).join(', '))
+console.log('events =', events.map((e) => e[0]).join(', '))
+console.log('effects =', effects.length)
+
+function fakeRes() {
+  return {
+    status: 0, headers: null, body: '',
+    writeHead(s, h) { this.status = s; this.headers = h },
+    write(chunk) { this.body += chunk; return true },
+    end(chunk) { if (chunk) this.body += chunk },
+  }
+}
+
+const route = routes[0]
+for (const p of ['/dsh-float-window/health', '/dsh-float-window/state', '/dsh-float-window/nope']) {
+  const res = fakeRes()
+  await route.handler({ method: 'GET', url: p, on: () => { } }, res)
+  console.log(p, '->', res.status, String(res.body).slice(0, 120))
+}
+
+// SSE 分支：只验证不抛异常且写出了 data:
+const res = fakeRes()
+await route.handler({ method: 'GET', url: '/dsh-float-window/events', on: () => { } }, res)
+console.log('events ->', res.status, res.headers['Content-Type'], JSON.stringify(res.body.slice(0, 80)))
+
+console.log('SMOKE OK')