/session-list

List all development sessions by:

1. Check if .sessions/ directory exists
2. List all .md files (excluding hidden files and .current-session)
3. For each session file:
   • Show the filename
   • Extract and show the session title
   • Show the date/time
   • Show first few lines of the overview if available
4. If .sessions/.current-session exists, highlight which session is currently active
5. Sort by most recent first

Present in a clean, readable format.