Integrate dedicated command line with current grid controls

[jasonsuhari]

Problem

The dedicated command-line feature exists on origin/feat/dedicated-command-line but forked before current main gained pane rename, swap, sleep, pane-contained mouse selection, usage labels, conversation footers, runtime resize, and worktree changes.

Requested behavior

Port the dedicated command bar onto latest main without regressing those current controls and UI behaviors.

Acceptance checks

• Dedicated command line can coexist with existing Alt shortcuts, mouse selection, footer, usage, resize, and worktree behavior.

pm test passes.

• A focused PR to main is opened for review.