Metered overage billing with automatic cap enforcement

Features

• Metered overage billing with automatic cap enforcement
• Payment failure grace period with auto-pause after expiry
• Agent-facing billing API for setup links and subscription status
• New /blog section with first post on AI agent email guardrails
• Free interactive tools section added to the portal
• Admin dashboard expansion: billing management, user admin, audit logs, health checks, and templates
• Plausible analytics added to portal and docs
• Automated blog publishing on a Mon/Wed/Fri schedule
• Redesigned landing page with a dedicated Problem section

Fixes

• Fixed tenants not being activated on API signup, blocking agent key usage
• Fixed silent tenant provisioning failures during signup
• Fixed redirect loop on the /docs route
• Fixed CTA buttons wrapping on mobile screens