feat(website): restyle landing benchmark cards, carousel, and topology cells

[NicholasKissel]

• Constrain the use-case carousel to the content column, keep the edge fade, and render each use case's icon
• Move the benchmark cards onto the light card surface with pine/ink ledger styling and pill tier selectors in a flush caption bar
• Anchor the benchmark info and help tooltips to their icons instead of the card frame
• Rescale the before/after topology cells for legibility and fill the agentOS panel with the VM chip run

[railway-app]

🚅 Deployed to the agentos-pr-1749 environment in agentos

Service	Status	Web	Updated (UTC)
agentos	😴 Sleeping (View Logs)	Web	Jul 14, 2026 at 8:12 am

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🚅 Environment agentos-pr-1749 in rivet-frontend has no services deployed.