Implements the first-run experience for the TUI as specified in the
specification's 'First-Run Experience' section (§ TUI Architecture).
On first launch (no personas configured), a centered ActorSelectionOverlay
widget is displayed guiding the user to select an actor. The overlay
supports keyboard navigation (j/k), fuzzy search (/), and confirmation
(enter). Selecting an actor creates a default persona and dismisses the
overlay.
Changes:
- Add src/cleveragents/tui/first_run.py: is_first_run() detection helper
and create_default_persona_for_actor() setup helper
- Add src/cleveragents/tui/widgets/actor_selection_overlay.py:
ActorSelectionOverlay widget with show/hide/navigate/search/confirm API
and render_actor_selection() pure rendering function
- Update src/cleveragents/tui/app.py: integrate first-run check in
on_mount(), yield ActorSelectionOverlay in compose(), add
_complete_first_run() method
- Update src/cleveragents/tui/widgets/__init__.py: export
ActorSelectionOverlay
- Add features/tui_first_run.feature + features/steps/tui_first_run_steps.py:
comprehensive Behave BDD tests covering all public API paths
ISSUES CLOSED: #1007
