feat(channelbridge): 群聊静默窗口合并与回合中续跑（M23）

主人 2026-10-23/24：「要让群聊聊天很自然，很流畅的做法」。群里「一鼓作气打三句」
此前会让她回三次；本片在**每会话车道头部**加一段静默等待，把这几句合成**一轮**回答
（批内每条仍是独立的一条消息，design/15 §2.1 不许拼成一条）。

四条不可走样：

- 🔴 主人私聊**结构性**无窗口：车道分 `newDirectLane`（无 batcher 字段、拿不到定时器
  工厂）与 `newBatchLane`，类型由 actor 元数据（IsOwner() && !IsGroupChat()）决定，
  配置无权翻转；
- 🔴 窗口内零丢失：唯一容器是车道队列（takeAll 单消费者取出），合并阶段无新增丢弃点
  （CoalescedDroppedTotal 恒 0）；超单批上限的**尾部回插队首**保序、锁内、发车前；
- 🔴 一条批 = 一个 turnID = 一次 loop.Run = 一条助手回复；
- 🔴 不改「回什么」：闸门仍逐条跑（prepareInbound 逐字搬运 M22 的 processFrom），
  被静默的消息进不了批。

实现落点：
- lane.go：direct/batch 两种车道 + front（回插队首）+ takeAll + 停机诚实登记；
- coalesce.go：生效参数解析、滑动窗口 + 绝对上限等待、发车原因与计数；
- coalesce_lane.go：攒批 → 拆分 → 陈旧度/闸门 → 发车；
- coalesce_prepare.go / coalesce_batch.go：processFrom 拆成 prepareInbound + runBatch；
- runtimeconfig/channels_coalesce.go：$DATA_DIR/config/coalesce.json（零新 .env 键）；
- gateway/admin_coalesce.go：GET/PUT /api/v1/admin/channels/coalesce（三态补丁 +
  writeAuth + 审计 channels.coalesce + 热生效），routes.go 两行注册（塔已批）；
- 前端：渠道总览页一张卡（六个旋钮；主人私聊只给只读说明，不给开关）。

M22 既有用例仍在（lane_test.go 夹具显式关窗以钉住车道本身）；stranger_test.go 的那条
按塔裁定 #4 改写：「已有回合在跑 ⇒ 只登记不回」变成排队回答（留 WARN，绝不静默）。

回归：go build/vet/test ./... 全绿；三包 -race 全绿；前端 tsc --noEmit + npm run build
+ 渲染测试 36 项通过。不 push、不重启后端、未改 .env 与 Docs/。

frontend/web/src/admin/modules/channels/coalesceCard.render.test.ts

@@ -0,0 +1,140 @@
+// 群聊静默窗口卡（M23）的**真实渲染**测试。
+//
+// 它钉住三件**呈现**的事（逻辑那一半在 CoalesceCard.tsx 的导出函数里）：
+//   ① 六个字段都有中文标签 + 一句人话说明（窗口/上限/单批/陌生人/开关）；
+//   ② 主人私聊**只给一行只读说明**（`ownerPrivate:"never"` 的呈现），**不给开关**；
+//   ③ 越界/非整数就地报错并拦住保存（后端那道 400 仍在，只是不让主人白跑）。
+//
+// 跑法（与 MemoryTidyTuningCard.render.test.ts 同）：
+//
+//   cd frontend/web \
+//     && ./node_modules/.bin/esbuild src/admin/modules/channels/coalesceCard.render.test.ts \
+//          --bundle --platform=node --format=cjs \
+//          --outfile=/tmp/cyrene-coalesce-card.render.test.cjs \
+//     && node /tmp/cyrene-coalesce-card.render.test.cjs
+//
+// `tsc --noEmit` 会对本文件做类型检查，因此它只从项目内导入、不 import node:*。
+
+import { createElement } from "react";
+import { renderToStaticMarkup } from "react-dom/server";
+import {
+  COALESCE_FIELDS,
+  COALESCE_HOT_LABEL,
+  OWNER_PRIVATE_NOTE,
+  CoalesceCardBody,
+  draftFromView,
+  parseCoalescePatch,
+  type CoalesceView,
+} from "./CoalesceCard";
+
+let checks = 0;
+
+function ok(cond: boolean, what: string): void {
+  checks += 1;
+  if (!cond) throw new Error(`FAILED: ${what}`);
+}
+
+function has(haystack: string, needle: string): boolean {
+  return haystack.includes(needle);
+}
+
+/** fixtureView 造一份 GET 响应形状的数据（代码默认 + 一条会话覆盖）。 */
+function fixtureView(overrides: Partial<CoalesceView> = {}): CoalesceView {
+  return {
+    path: "/data/config/coalesce.json",
+    present: true,
+    hot: true,
+    default: {
+      enabled: true,
+      windowMs: 2000,
+      maxWaitMs: 6000,
+      maxBatchMessages: 24,
+      applyToStrangers: true,
+      strangerWindowMs: 2000,
+    },
+    patch: {},
+    conversations: {
+      "telegram|group:-20": {
+        enabled: false,
+        windowMs: 2000,
+        maxWaitMs: 6000,
+        maxBatchMessages: 24,
+        applyToStrangers: true,
+        strangerWindowMs: 2000,
+      },
+    },
+    rules: {
+      windowMs: [300, 15000],
+      maxWaitMs: [300, 30000],
+      maxBatchMessages: [1, 50],
+      clamp: "clamp",
+      flushReasons: ["quiet", "max_wait", "all_stale", "off", "stop"],
+    },
+    ownerPrivate: "never",
+    ...overrides,
+  };
+}
+
+function render(view: CoalesceView, draftOverride?: Partial<ReturnType<typeof draftFromView>>): string {
+  const draft = { ...draftFromView(view), ...(draftOverride ?? {}) };
+  const check = parseCoalescePatch(view, draft);
+  return renderToStaticMarkup(
+    createElement(CoalesceCardBody, {
+      view,
+      draft,
+      errors: check.errors,
+      busy: false,
+      receipt: null,
+      savedView: null,
+      onDraftChange: () => undefined,
+      onSave: () => undefined,
+    })
+  );
+}
+
+function main(): void {
+  const view = fixtureView();
+  const html = render(view);
+
+  // ① 六个字段的中文标签 + 说明都在，且「主人私聊」只有说明、没有开关。
+  for (const field of COALESCE_FIELDS) {
+    ok(has(html, field.label), `field label missing: ${field.label}`);
+    ok(has(html, field.hint), `field hint missing for ${field.key}`);
+    ok(has(html, field.key), `field key not shown for ${field.key}`);
+  }
+  ok(has(html, OWNER_PRIVATE_NOTE), "owner-private read-only note missing");
+  ok(has(html, "面板没有开关"), "owner-private note must say the panel has no switch for it");
+  ok(has(html, COALESCE_HOT_LABEL), "hot label missing");
+  ok(has(html, "/data/config/coalesce.json"), "config path not shown");
+  ok(has(html, "telegram|group:-20"), "per-conversation override not listed");
+  ok(has(html, "300–15000ms"), "window rules not shown");
+  ok(has(html, "quiet"), "flush reasons not shown");
+
+  // ② 三态补丁：只有改过的键才写；没改 ⇒ 空补丁。
+  const unchanged = parseCoalescePatch(view, draftFromView(view));
+  ok(Object.keys(unchanged.patch.default).length === 0, "unchanged draft must produce an empty patch");
+  ok(unchanged.changed.length === 0, "unchanged draft must report no changed keys");
+
+  const changed = parseCoalescePatch(view, { ...draftFromView(view), windowMs: "3000" });
+  ok(changed.patch.default.windowMs === 3000, "changed window must land in the patch");
+  ok(changed.changed.length === 1, `only the changed key may be written, got ${changed.changed.join(",")}`);
+
+  // ③ 坏值就地报错，且补丁里不含那个键（不会把一半好一半坏的东西发出去）。
+  const bad = parseCoalescePatch(view, { ...draftFromView(view), windowMs: "10", maxBatchMessages: "abc" });
+  ok(bad.errors.windowMs !== undefined, "out-of-range window must be reported");
+  ok(bad.errors.maxBatchMessages !== undefined, "non-numeric batch must be reported");
+  ok(bad.patch.default.windowMs === undefined, "invalid window must not be sent");
+  ok(bad.patch.default.maxBatchMessages === undefined, "invalid batch must not be sent");
+
+  // 绝对上限必须 ≥ 窗口（下层规则由面板现算，不能只信后端）。
+  const waitTooSmall = parseCoalescePatch(view, { ...draftFromView(view), windowMs: "5000", maxWaitMs: "3000" });
+  ok(waitTooSmall.errors.maxWaitMs !== undefined, "maxWait below the window must be rejected");
+
+  const badHtml = render(view, { windowMs: "10" });
+  ok(has(badHtml, "取值范围"), "invalid draft must render an inline error");
+  ok(has(badHtml, "有坏值，未提交"), "invalid draft must block the save button");
+
+  process.stdout.write(`coalesce card render: ${checks} checks passed\n`);
+}
+
+main();