feat(guild): wake_mapping, per-recipient wakeup, discuss/work turn engine, channel join/leave

- wake_mapping table; triage onDuty (auto-added member) / custom listeners
- per-recipient wakeup metadata on message.created (one message-id; added
  only at push). Rules: author=false; triage/custom=wake_mapping only;
  general=all; report=none
- discuss/work rotation: channel_turn_state (order/currentSpeaker/round
  events/cross-round no-reply streak); null activation, queue-jump,
  /no-reply pass, all-/no-reply pause, end-of-round shuffle (trailing
  no-reply run to tail, head shuffled, first != last normal speaker)
- slash-command registry (/no-reply, /force-proceed); registered commands
  intercepted and never delivered; guild-authored /ack persisted
- POST /channels/:id/join|leave; leave cleans channel_members, wake_mapping
  and turn-state order

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/channels/channels.controller.ts

@@ -1,4 +1,4 @@
-import { Body, Controller, Get, Post, Query, Req, UnauthorizedException } from '@nestjs/common';
+import { Body, Controller, Get, Param, Post, Query, Req, UnauthorizedException } from '@nestjs/common';
 import { ChannelsService } from './channels.service';
 
 // ApiKeyGuard attaches the introspected Center user id onto the request.
@@ -27,8 +27,24 @@ export class ChannelsController {
         xType: body.xType as string | undefined,
         isPublic: Boolean(body.isPublic),
         memberUserIds: Array.isArray(body.memberUserIds) ? (body.memberUserIds as string[]) : [],
+        onDuty: body.onDuty as string | undefined,
+        listeners: Array.isArray(body.listeners) ? (body.listeners as string[]) : [],
       },
       userId,
     );
   }
+
+  @Post(':id/join')
+  join(@Req() req: AuthedRequest, @Param('id') channelId: string) {
+    const userId = req.userId ?? '';
+    if (!userId) throw new UnauthorizedException('missing user');
+    return this.channelsService.joinChannel(channelId, userId);
+  }
+
+  @Post(':id/leave')
+  leave(@Req() req: AuthedRequest, @Param('id') channelId: string) {
+    const userId = req.userId ?? '';
+    if (!userId) throw new UnauthorizedException('missing user');
+    return this.channelsService.leaveChannel(channelId, userId);
+  }
 }