fix(index): show 30d chain metrics

[ignacio-rsg]

Summary

• filter homepage top chains data to the last 30 days
• keep chains ordered by 30-day CU descending
• relabel the homepage Chains widget columns as 30-day metrics

Testing

• pnpm --filter @info/api test -- routes-index
• pnpm --filter @info/api typecheck
• pnpm --filter @info/web typecheck
• git diff --check

Local verification

• Verified locally on http://localhost:5324 with the API on port 5325.
• Used a temporary local indexer adapter outside the repo only for visual verification; no local visualization files are included in this PR.