Add NSToolbar with a gear dropdown to the chat window, replacing the
broken right-click menu bar interaction.
Gear menu: Talk Mode toggle, Settings (Cmd+,), Quit (Cmd+Q).
Also adds Talk Mode toggle to Settings > General.
Add shared native chat handling for /new, /reset, and /clear.
This also aligns main session key handling in the shared chat UI and includes follow-up test and CI fixes needed to keep the branch mergeable.
Co-authored-by: Nachx639 <71144023+Nachx639@users.noreply.github.com>
Co-authored-by: Luke <92253590+ImLukeF@users.noreply.github.com>