GitHub Copilot CLI session appeared to continue consuming AI credits after all visible tasks were completed.

## Summary

GitHub Copilot CLI session appeared to continue consuming AI credits after all visible tasks were completed.

## Environment

- GitHub Copilot CLI version: 1.0.75
- Mode: Interactive CLI session
- Session limit enabled: No
- Observed behavior: Session showed approximately 97.8% AI credit usage after the visible tasks completed. No further user prompts or interactions were made. Later, the session reached 100%.

## Expected behavior

After all visible tasks are complete and no user interaction occurs, AI credit usage should either remain stable or the CLI should clearly indicate that background work is still running and consuming credits.

## Actual behavior

The session moved from approximately 97.8% to 100% without additional user interaction.

## Question

Is this expected due to final response accounting, subagent completion, or background compaction? If so, can the CLI expose clearer status so users can distinguish between:
1. truly idle waiting-for-input state, and
2. background/session-finalization work that may still consume AI credits?

## Supporting context

GitHub documentation says session limits include model calls, subagents, and background work like compaction, and that session limits are soft caps because usage is only known after a response returns.

Inizia riproducendo il comportamento in GitHub Copilot CLI 1.0.75 usando una sessione interattiva, quindi monitora l'utilizzo dei crediti dopo il completamento dell'attività visibile senza ulteriori prompt. Confronta la transizione osservata con il trattamento documentato delle chiamate al modello, dei subagents e della compattazione in background; completato significa che l'utilizzo successivo all'attività è spiegato e che lo stato inattivo o in background è chiaramente distinguibile.

Scritto dal modello di indicizzazione a partire dal testo della issue.