Auth: redesigned login and signup pages with half-page interactive dot pattern layout

Features

• Auth: redesigned login and signup pages with half-page interactive dot pattern layout
• Free plan: promo banner and onboarding checklist for new accounts
• Journeys: double opt-in journey integration for email list subscriptions
• DogFood agent: internal automated customer testing agent
• Docs: threads, outbound, and approval queues API documentation
• Docs: feature documentation pages for templates, journeys, lists, analytics, and more

Fixes

• Free plan: restrict to 1 mailbox and 0 custom domains
• Free plan: fix signup crash when provisioning free accounts
• Events: restore /v1/events/inbound by adding events back to nativeRoutes
• Tests: fix experiment start/stop smoke tests to pass tenantId in body