feat: IM session list relative time + /session N index binding

Local UX enhancements on top of upstream ce8b9e8:
- harness-client.mjs: add toEpochMs/sessionTimeMs, attach time to sessions
- workspace-command.mjs: /sessionlist relative time, /session N index binding

src/channels/shared/harness-client.mjs

@@ -40,6 +40,37 @@ function workspaceFromList(workspacePath, workspaceList) {
   return workspace;
 }
 
+function toEpochMs(value) {
+  if (typeof value === 'number' && Number.isFinite(value)) {
+    return value < 1e12 ? value * 1000 : value;
+  }
+  if (typeof value === 'string' && value) {
+    const parsed = Date.parse(value);
+    if (!Number.isNaN(parsed)) return parsed;
+  }
+  return null;
+}
+
+function sessionTimeMs(summary) {
+  if (!summary || typeof summary !== 'object') return null;
+  const candidates = [
+    summary?.header?.lastActivityAt,
+    summary?.header?.updatedAt,
+    summary?.header?.createdAt,
+    summary?.projections?.values?.lastActivityAt,
+    summary?.projections?.values?.updatedAt,
+    summary?.projections?.values?.createdAt,
+    summary?.lastActivityAt,
+    summary?.updatedAt,
+    summary?.createdAt,
+  ];
+  for (const value of candidates) {
+    const ms = toEpochMs(value);
+    if (ms !== null) return ms;
+  }
+  return null;
+}
+
 function workspaceSessions(workspace, archivedSessionIds, sessionList) {
   if (!Array.isArray(sessionList?.items)) {
     throw new Error('Harness returned an invalid response for session.list');
@@ -54,7 +85,7 @@ function workspaceSessions(workspace, archivedSessionIds, sessionList) {
     sessions: workspace.sessionIds.map((sessionId) => {
       const summary = summaries.get(sessionId);
       const title = summary?.projections?.values?.title;
-      return {
+      const session = {
         sessionId,
         title: typeof title === 'string' ? title : null,
         archived: archived.has(sessionId),
@@ -62,6 +93,9 @@ function workspaceSessions(workspace, archivedSessionIds, sessionList) {
         origin: summary?.origin === 'subagent' ? 'subagent' : null,
         summaryAvailable: summary !== undefined,
       };
+      const time = sessionTimeMs(summary);
+      if (time !== null) session.time = time;
+      return session;
     }),
   };
 }

src/channels/shared/workspace-command.mjs

@@ -13,7 +13,7 @@ const MAX_COMMAND_MESSAGE_LENGTH = 1_800;
 const MAX_SESSION_ID_LENGTH = 256;
 const UNSAFE_DISPLAY_TEXT = /[\p{Cc}\p{Cf}\p{Zl}\p{Zp}]/u;
 const UNSAFE_DISPLAY_TEXT_GLOBAL = /[\p{Cc}\p{Cf}\p{Zl}\p{Zp}]+/gu;
-const SESSION_BIND_USAGE = '用法：/session Session ID';
+const SESSION_BIND_USAGE = '用法：/session Session ID 或 序号（/session N）';
 const SESSION_LIST_USAGE = [
   '用法：',
   '/sessionlist  列出当前工作区会话',
@@ -175,6 +175,25 @@ async function resolveSessionListWorkspace(selector, harness) {
   return selected;
 }
 
+function formatSessionRelativeTime(value) {
+  const ms = typeof value === 'number' && Number.isFinite(value) ? value : null;
+  if (ms === null) return '';
+  const date = new Date(ms);
+  if (Number.isNaN(date.getTime())) return '';
+  const pad = (n) => String(n).padStart(2, '0');
+  const hm = `${pad(date.getHours())}:${pad(date.getMinutes())}`;
+  const startOfDay = (d) => new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime();
+  const now = new Date();
+  const dayDiff = Math.round((startOfDay(now) - startOfDay(date)) / 86_400_000);
+  if (dayDiff === 0) return `今天 ${hm}`;
+  if (dayDiff === 1) return `昨天 ${hm}`;
+  if (dayDiff === 2) return `前天 ${hm}`;
+  if (date.getFullYear() === now.getFullYear()) {
+    return `${date.getMonth() + 1}月${date.getDate()}日 ${hm}`;
+  }
+  return `${date.getFullYear()}年${date.getMonth() + 1}月${date.getDate()}日`;
+}
+
 function sessionListMessage(workspace, sessions) {
   const rows = sessions.map((session) => {
     const sessionId = safeDisplayText(session?.sessionId);
@@ -182,7 +201,9 @@ function sessionListMessage(workspace, sessions) {
     const title = session?.summaryAvailable === false
       ? '标题暂不可用'
       : safeDisplayText(session?.title) || '暂无标题';
-    return `${title}${session?.archived === true ? '（已归档）' : ''}\n   ID: ${sessionId}`;
+    const timeText = formatSessionRelativeTime(session?.time);
+    const annotation = `${timeText ? ` · ${timeText}` : ''}${session?.archived === true ? '（已归档）' : ''}`;
+    return `${title}${annotation}\n   ID: ${sessionId}`;
   });
   if (rows.length === 0) return `工作区：${workspace}\n该工作区暂无会话。`;
   return [
@@ -191,7 +212,7 @@ function sessionListMessage(workspace, sessions) {
     '',
     ...rows.map((row, index) => `${index + 1}. ${row}`),
     '',
-    '绑定用法：/session Session ID',
+    '绑定用法：/session Session ID 或 序号（/session N）',
   ].join('\n');
 }
 
@@ -247,7 +268,29 @@ function sessionBindErrorMessage(error) {
 
 async function runSessionBindCommand(command, harness, conversationKey) {
   const match = SESSION_BIND_COMMAND.exec(command);
-  const sessionId = match?.[1];
+  let sessionId = match?.[1];
+  if (typeof sessionId === 'string' && /^\d+$/u.test(sessionId)) {
+    // 序号模式：把 /session N 解析成当前工作区会话列表中的第 N 个会话
+    if (typeof harness?.listWorkspaceSessions !== 'function'
+      || typeof harness?.currentWorkspace !== 'function') {
+      return commandResult('当前机器人暂不支持按序号绑定，请使用 /session Session ID。');
+    }
+    const selected = await selectedWorkspacePath(harness.currentWorkspace());
+    if (selected.error) return commandResult(selected.error);
+    let listed;
+    try {
+      listed = await harness.listWorkspaceSessions(selected.workspace);
+      harness.assertWorkspaceScope?.();
+    } catch {
+      return commandResult('暂时无法获取会话列表，请稍后重试。');
+    }
+    const position = Number(sessionId);
+    if (!Number.isSafeInteger(position) || position < 1
+      || position > (listed?.sessions?.length ?? 0)) {
+      return commandResult('会话序号不存在，请先执行 /sessionlist 查看序号。');
+    }
+    sessionId = listed.sessions[position - 1].sessionId;
+  }
   if (!validSessionId(sessionId)) return commandResult(SESSION_BIND_USAGE);
   if (typeof harness?.bindWorkspaceSession !== 'function') {
     return commandResult('当前机器人暂不支持绑定已有会话。');