Feature Request: Periodic Buffer Persistence for Crash Recovery

1. Buffer content should be restored from the most recent periodic save
2. A message should indicate the session was recovered: `[Session recovered - buffer content from HH:MM:SS]`
3. Metadata should be displayed showing:
   - Working directory at time of crash
   - Last command executed (if available)
   - Process that was running (e.g., `pwsh.exe`, `claude`, `ssh`)