feat(cast): add cast erc20 with subcommands balance, transfer, approve, allowance

[marcvernet31]

Motivation

Refactor usage of --erc20 flag into command cast erc20. Onboard additional actions as defined here: #12095

Solution

Introduce a dedicated cast erc20 command with various subcommands for common ERC20 operations:

• cast erc20 balance <TOKEN> <ACCOUNT> - Query ERC20 token balance (replaces cast balance --erc20)
• cast erc20 transfer <TOKEN> <TO> <AMOUNT> - Transfer tokens using transfer(address,uint256)
• cast erc20 approve <TOKEN> <SPENDER> <AMOUNT> - Approve token spending using
  approve(address,uint256)
• cast erc20 allowance <TOKEN> <OWNER> <SPENDER> - Query allowance using
  allowance(address,address)

Also added a deprecation warning on the --erc20 command.

Tested with a local Anvil node.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[grandizzy]

@marcvernet31 thank you! since you mentioned you tested with an anvil node, we could add same in unit tests, here's an example of a cast test that starts anvil and then send cast mktx commands, could you replicate your tests this way?

foundry/crates/cast/tests/cli/main.rs

Lines 1639 to 1665 in 1b115d8

	casttest!(mktx_raw_unsigned_no_from_missing_chain, async |_prj, cmd| {
	// As chain is not provided, a query is made to the provider to get the chain id, before the tx
	// is built. Anvil is configured to use chain id 1 so that the produced tx will be the same
	// as in the `mktx_raw_unsigned` test.
	let (_, handle) = anvil::spawn(NodeConfig::test().with_chain_id(Some(1u64))).await;
	cmd.args([
	"mktx",
	"--nonce",
	"0",
	"--gas-limit",
	"21000",
	"--gas-price",
	"10000000000",
	"--priority-gas-price",
	"1000000000",
	"0x0000000000000000000000000000000000000001",
	"--raw-unsigned",
	"--rpc-url",
	&handle.http_endpoint(),
	])
	.assert_success()
	.stdout_eq(str![[
	r#"0x02e80180843b9aca008502540be4008252089400000000000000000000000000000000000000018080c0
	"#
	]]);
	});

[0xrusowsky]

great job!
left some minor nits

[0xrusowsky]

please rmv the todo.
you can add an alias for who instead if u want.

[0xrusowsky]

Suggested change

	sh_warn!("--erc20 flag is deprecated, use cast erc20 balance instead")?;
	sh_warn!("--erc20 flag is deprecated, use `cast erc20 balance` instead")?;

[0xrusowsky]

can we rename it to owner to stick to the ERC20 interface? account was previously used cause --erc20 was just a flag on top of the cmd that would get teh eth balance of an account.

[onbjerg]

this shows up in the help output, so please fix this up

Suggested change

	/// ERC20 token subcommands.
	/// CLI arguments for `cast tx-pool`.
	/// Interact with ERC20 tokens.