ShipIt UI: Ethereum 101 final crowdfunding experiment UI

\`labs/ethereum-101/UseIt.tsx\` ships the minimal cut of #20's card 22: fund from three accounts, goal bar, public ledger, goal-reached beat. The component carries a TODO(revamp) for the rest:

From #20:

- Nicely showcase 3 different accounts (addresses from SE-2 component) with thir initial balance
- Show a progress bar towards goal
- A refund button
...

Start with labs/ethereum-101/UseIt.tsx and its TODO(revamp), then compare the existing minimal cut with card 22 in issue #20 and the account addresses from the SE-2 component. Complete the remaining crowdfunding UI described there, including the account balances, goal progress, and refund interaction, while preserving the existing ledger and goal-reached behavior.

Written by the indexing model from the issue text.