Several broken/dead links on compound.finance

[fteixeira852]

Hey team, was browsing compound.finance and noticed a few links on the site that are broken or lead to dead pages:

• Zapper link goes to a 404 (zapper.fi/save doesn't exist anymore)
• Eidoo link — site appears to be completely down
• PoolTogether link — pooltogether.us is dead
• TokenTax — returns a 403/blocked page
• Several testnet explorer links still reference deprecated networks (Kovan, Rinkeby, Ropsten) that were shut down after the Merge

Not urgent obviously, but might be worth cleaning up since they're visible to users browsing the ecosystem/integrations page.

Thanks!