feat(react-email): Bottom layout for toolbar

[gabrielmfern]

• add dev:preview command
• update to use flex layouts
• remove commented code
• remove toolbar from sidebar
• very initial draft of bottom toolbar
• do more design work
• implement initial spam assassin on bottom layout
• add animation for active tab indicator
• add sf mono as font-mono
• improve sorting
• implement the reloading functionality
• implment initial version of link & image checker
• improve accuracy for http rule
• lint
• fix tests