replace `TRANSACTION_CONFIRMATION_WAIT_SECS` with receipt confirmations

ok I see you do a similar thing elsewhere (`TRANSACTION_CONFIRMATION_WAIT_SECS`). You can fix all of those in a separate PR. That should improve the setup time by a few minutes.

_Originally posted by @wjmelements in https://github.com/FilOzone/foc-devnet/pull/57#discussion_r2770365134_

We want to avoid sleeping between transactions to reduce the time it takes to run everything.

`cast send` waits for confirmation by default. Might need `--confirmations 2` if the state isn't updated after 1 confirmation.

Instead of waiting between transactions, increment nonce and pass it to `cast --async` when possible. Only wait for the last transaction in a sequence. For deploying transactions, you can calculate the contract address ahead of time via sender+nonce, so it is not necessary to await a transaction just to obtain an address.

Separately, the devnet block time should be configurable. Please ensure it has been set to some low value.

Locate every use of TRANSACTION_CONFIRMATION_WAIT_SECS and the transaction setup paths that invoke cast send. Compare those waits with cast's receipt confirmation and async options; done means transaction sequences avoid unnecessary sleeps, only the final transaction is awaited where appropriate, and the devnet block time is configurable at a low value.

Written by the indexing model from the issue text.