fix: register /cancel as a proper command

Previously /cancel was intercepted inside the 'unknown' branch, and the
comparison used the command WITHOUT the leading slash while parseCommand
returns it WITH one ('/cancel') — the check never matched, so /cancel
always fell through to the unknown-command reply, even with a pending
ask/approval.

Now a first-class command (menu included): closes the TG-side
answer/approval channel when one is pending, otherwise reports that
nothing is awaiting a reply.

src/bridge.ts

@@ -218,6 +218,7 @@ export class TelegramBridge {
       { command: 'stop', description: '中止当前正在运行的任务' },
       { command: 'mission', description: '查看任务清单与完成情况' },
       { command: 'new', description: '在当前工作区新开对话并附着' },
+      { command: 'cancel', description: '关闭 TG 端作答/审批（Web 端仍可答）' },
       { command: 'help', description: '显示帮助' },
     ]).then(() => {
       this.ctx.logger.info('dsh-telegram-channel: bot commands registered')
@@ -320,17 +321,18 @@ export class TelegramBridge {
       case 'new':
         await this.newSessionHere(chatId)
         return
-      case 'unknown':
+      case 'cancel': {
         // /cancel closes the TG-side answer/approval channel; the UI side stays open.
-        if (parsed.command === 'cancel') {
-          let cancelled = false
-          if (this.pendingApprovalsTG.delete(String(chatId))) cancelled = true
-          if (this.pendingAsks.delete(String(chatId))) cancelled = true
-          if (cancelled) {
-            await this.enqueueNotice(chatId, '已关闭 TG 端作答/审批（该问题仍可在 Web 端回答）')
-            return
-          }
-        }
+        let cancelled = false
+        if (this.pendingApprovalsTG.delete(String(chatId))) cancelled = true
+        if (this.pendingAsks.delete(String(chatId))) cancelled = true
+        if (cancelled)
+          await this.enqueueNotice(chatId, '已关闭 TG 端作答/审批（该问题仍可在 Web 端回答）')
+        else
+          await this.client.sendMessage(chatId, '当前没有待作答的提问或审批')
+        return
+      }
+      case 'unknown':
         await this.client.sendMessage(chatId, MSG.unknown(parsed.command))
         return
       case 'plain': {

src/commands.ts

@@ -73,6 +73,7 @@ export type ParsedCommand =
   | { type: 'stop'; text: string }
   | { type: 'mission'; text: string }
   | { type: 'new'; text: string }
+  | { type: 'cancel'; text: string }
   | { type: 'unknown'; command: string; text: string }
   | { type: 'plain'; text: string }
 
@@ -107,6 +108,8 @@ export function parseCommand(text: string): ParsedCommand {
     case '/new':
     case '/create':
       return { type: 'new', text }
+    case '/cancel':
+      return { type: 'cancel', text }
     default:
       return { type: 'unknown', command, text }
   }