Feature request: acknowledge /remote-control activation on the parent (local) session

Request

When /remote-control is activated and/or a remote device connects to drive the session, show recognition in the parent (local) session — e.g. a line/banner such as:

🔗 Remote control active — connected from <device / browser> at <time>

…and a matching "remote control disconnected" notice when the remote session ends.

Why

Today the parent session gives no confirmation that remote control is active or that a remote client has connected. A visible indicator would help on two fronts:

• Confidence — the user can see it actually worked, rather than wondering whether the command did anything.
• Security / awareness — the user knows when and that another device is controlling the session.

Context

Surfaced while diagnosing a silent /remote-control failure (related: #63964). The complete lack of any parent-session acknowledgement made it harder to tell whether the command had taken effect at all.