When clicking a draft placeholder ("New Agent Thread" tab) or confirming
one via keyboard, the agent panel now always opens. Previously it only
focused the panel if it was already visible.

Regular threads and drafts with IDs already opened the panel through
`activate_draft` and `load_agent_thread_in_workspace`. The project
header click continues to activate the workspace without forcing the
panel open.

cc @danilo-leal

Release Notes:

- N/A