Cardano Updates

Adversarial mempool experiments

Landing page enhancements:
- Add Live Tracker section with static preview image linking to tracker
- Add Mempool Simulation section with embedded iframe
- Alternate section layouts (visual left/right) for visual variety
- Style "Stay up to date" section with featured purple gradient background
- Fix LinkButton hover effect for light theme (purple gradient)
- Remove document icon from LinkButton

Mempool simulator embed mode:
- Add URL parameters: embed, autoPlay, hideControls, hideStats, etc.
- Auto-start simulation when iframe becomes visible (IntersectionObserver)
- Support speed parameter for embed playback

Implements Cardano-style P2P peer selection to make front-running more
difficult through dynamic topology changes. Peers cycle through cold,
warm, and hot states with periodic churn events.

Key changes:
- Add PeerManager class to track peer states per node
- Add PeerChurn simulation event for periodic state transitions
- Modify tx propagation to only use hot upstream peers in P2P mode
- Add CLI flags: --p2p, --p2p-hot-peers, --p2p-churn-interval,
  --p2p-demotion-prob

The feature is toggleable (off by default) to preserve existing
static topology behavior.

Replace cold/warm/hot state machine with a simpler active set model:
- Each node maintains a subset of active peers from topology
- Churn probabilistically replaces active peers with inactive ones
- Removes PeerState type and PeerInfo interface
- Renames CLI options: --p2p-hot-peers → --p2p-active-peers,
  --p2p-demotion-prob → --p2p-churn-prob

This mirrors Cardano's peer selection governor behavior with partial,
probabilistic churn rather than wholesale peer set replacement.

Also convert config to yaml for it allows comments

- Remove redundant console.log in cli.ts (already logged via logger.fatal)
- Remove duplicate Canvas useEffect that called draw() on every change
- Use hoveredNodeRef instead of state in draw() to avoid recreation on mouse move
- Throttle force layout position updates with requestAnimationFrame
- Only update event log state when lengths actually change
- Only update animatedTxs state when count changes

These changes prevent the force layout from triggering 100+ React
re-renders per second during initial settling.