Adds AgentStripView (status/model/turns/tokens row, worktree path,
branch line, action buttons), SessionTerminalView (scrollable log with
auto-scroll on CollectionChanged, prompt TextBox with Enter binding),
and replaces DetailsIslandView placeholder with full ScrollViewer layout
containing editable title, agent strip, terminal, subtasks, notes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
