Optimization: Migrate from ethers.js to viem for smaller bundle size

[jubalm]

Problem

The ethers.js library is large (~200KB minified), which impacts initial page load times and bundle size for the website.

Proposed Solution

Migrate from ethers.js to viem (a lighter, tree-shakeable Ethereum library ~15KB) for the blockchain data collection script.

Scope

• scripts/calculate-fork-risk.ts - the only file using ethers.js
• No changes to frontend code

Risk & Verification Needed

This is a critical data pipeline - the script calculates real fork risk values displayed on the live site. Before switching:

1. Add test coverage to verify fork risk calculations
2. Compare output before/after migration (run both versions against same RPC)
3. Coordinate timing with low-traffic period for quick rollback if needed

Technical Notes

• ethers.js v6 is currently being used
• viem has similar APIs but may require refactoring RPC calls
• Consider keeping both temporarily with a flag to switch between them

Impact

• Bundle size reduction: ~185KB (estimated)
• Improved Time to Interactive (TTI)