Bug Description

Telegram forum supergroup messages completely fail to reach the OpenClaw gateway, despite DM working perfectly.

Steps to Reproduce

1. OpenClaw 2026.2.26 (updated this morning)
2. Telegram forum supergroup with topics enabled (is_forum:true)
3. Bot is admin with full permissions
4. GroupPrivacy disabled in BotFather
5. Config has requireMention: false and groupPolicy: allowlist
6. Send any message in the group (plain text or with @mention)

Expected Behavior

Messages should reach the gateway and trigger agent response.

Actual Behavior

• Messages do NOT reach the gateway at all
• No entries in gateway logs for group messages
• getUpdates API call returns empty (messages consumed by gateway polling)
• DM works perfectly - messages reach gateway and trigger agent runs
• Bot can send messages to group successfully (outbound works)

Evidence

• Bot admin status confirmed via getChatMember
• getMe shows can_read_all_group_messages: true
• Gateway polling is active (confirmed by 409 conflict when running curl)
• Regular Telegram API can see the group and bot is admin
• DM is functional - test message triggered agent run with messageChannel=telegram

Environment

• OpenClaw 2026.2.26
• Ubuntu Linux
• Telegram Bot API
• Forum supergroup (no main chat, topics only)

Config

"channels": {
  "telegram": {
    "enabled": true,
    "groupPolicy": "allowlist",
    "accounts": {
      "default": {
        "enabled": true,
        "dmPolicy": "pairing",
        "groups": {
          "-1003832125707": {
            "requireMention": false
          }
        }
      }
    }
  }
}

Additional Notes

This appears to be related to existing issue #28201 (Slash commands silently ignored in Telegram forum group topics), but more severe - even regular text messages are not reaching the gateway at all.

DM works, group doesn't. This is a fresh install / fresh config issue.