[cmpadden]

Summary

• Add optional read-only tmux monitors in the parent Pi window: first monitor opens on the right, additional monitors stack in that column with balanced heights.
• Preserve Pi focus and unrelated panes; serialize layout changes, reconcile manually closed monitors, and close viewers automatically on completion/cancellation/shutdown.
• Configure display through pi-delegate.display in Pi settings (tmux or the default hidden); enable tmux in the dotfiles configuration without requiring an environment variable.
• Show bounded, private live snapshots with status, usage, tool activity, and output; gracefully fall back to hidden execution when tmux is unavailable.
• Add short delegate labels and compact parent tool rows, with full details available through Ctrl+O.

Validation

• All 40 delegate tests pass, including real isolated tmux tests for concurrent launches, balanced geometry, focus, unrelated panes, manual closure, replacement monitors, and cleanup.
• Live-tested three concurrent delegates in the parent tmux window; monitor heights were 16, 16, and 15 rows.
• make format
• git diff --check and staged diff audit for secrets/runtime state
• make lint: all available checks pass, but both ShellCheck hooks are blocked because shellcheck is not installed.

Only delegate extension files and its settings entry are included; unrelated local dotfile changes are excluded.