run_tui() now calls discover_sessions() before entering the event loop,
converts each SessionRef to SessionListItem (sorted most-recent-first),
and assigns to state.sessions. Failures silently yield an empty list.
Fixes claudbg-zi1d
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Quit dialog: centered 26×5 Clear+Block overlay triggered by q/Q,
confirms with q, dismisses with Esc. Help modal: centered 32×14 overlay
triggered by ?, lists all keyboard shortcuts, dismisses with Esc.
Both modals intercept all input while open. Wired into run.rs dispatch.
Closes claudbg-1e1c
Closes claudbg-1tlk
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Implements run_tui() with RAII terminal guard (TerminalGuard), panic hook
for safe cleanup, and 50ms poll event loop. Placeholder renderer draws a
bordered box. Wires into stubs.rs replacing the coming-soon stub.
Closes claudbg-ut9q
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>