CodeRabbit reframes Advanced around architectural insights (copy only)

Advanced plan reframed around architectural insights: tagline changed from "Our most comprehensive plan with advanced code review" to "Deeper code review with architectural insights", and its card bullets now surface "Blast radius and architectural impact analysis" plus reworded "Everything in Team" and "Security review of every PR". The Compare-plans table is unchanged and already listed Blast radius and Architectural impact as Included for Advanced, so this is presentation only. Enterprise separately takes over the "Our most comprehensive plan" framing. No price, plan, or entitlement changes.