feat: let the operator purge a group's chat (MNP 6.1)

Signed chat_purge from the Chat settings deletes every stored message;
epoch keys and attachments stay. The ack is broadcast so open chat
panels empty.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/transport-chat.js b/packages/meshbay-hub/src/meshbay_hub/static/transport-chat.js
index 96e06d7..9ce07bc 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/transport-chat.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/transport-chat.js
@@ -78,6 +78,21 @@ extendTransport(class {
   }
 
   /**
+   * Delete every stored message of this group's chat. Operator only, and
+   * signed; the subject is the group id. The node broadcasts `chat_purge_ack`,
+   * which empties every open chat panel, this one included.
+   */
+  async purgeChat(signFn) {
+    const groupId = this._groupId || '';
+    const msg = await this._sendAndWait({ type: 'chat_purge', v: '6.1' });
+    if (msg.type === 'error') throw new Error(msg.detail);
+    if (msg.type === 'admin_challenge') {
+      return this._authorizeAdminOp(msg, 'chat_purge', groupId, signFn);
+    }
+    return msg;
+  }
+
+  /**
    * A page of chat history, newest first by default.
    *
    * `before` is a message id, not a timestamp: it pages backwards from the