Quickstart "Essential commands" table mixes shell and session commands without distinction

The "Essential commands" table on the Quickstart page lists shell commands and interactive session commands in a single flat list, which is confusing for new users.

Current state

The table includes:

• Shell commands (claude, claude "task", claude -p "query", claude -c, claude -r)
• Session commands (/clear, /help)
• exit (which should probably be /exit to match the /command convention used inside sessions)

All are presented as if they belong to the same context.

Suggested improvements

1. Split the table into two sections — e.g., "Shell commands" (run from your terminal) and "Session commands" (run inside Claude Code).
2. Change exit to /exit for consistency with other session commands like /clear and /help.

This would help new users understand where each command is meant to be used.