feat(admin): bot management (list, verify, create, delete)

- Add a Bots admin tab: list/search bots with a dedicated read query
  (users.is_bot, excluded from the accounts list), showing owner and
  system-vs-user type
- Create system bots from the admin via a new bot.create command that
  reuses the existing bot provisioning flow; the token is shown once
- Delete user-created bots via a new bot.delete command backed by a
  dedicated Postgres DeleteBotAccount (revokes sessions, purges private
  state, releases username, drops the bots row, tombstones the user);
  system service bots are rejected
- Verified badge toggling reuses the existing set-verified command
- All write paths go through the dry-run/confirm + audit command pipeline
- Rebuild dist bundle

cmd/telesrv/main.go

@@ -921,6 +921,7 @@ func run(logger *zap.Logger) error {
 		ChannelNotifier: router,
 		Messages:        messagesService,
 		Gifts:           giftsService,
+		Bots:            botsService,
 	})
 	// bot session 撤销、在线通知与 @ChatBot 流式草稿推送经 router 实现（需 tg.* 边界），
 	// router 创建后注入。