Add confirmation prompt for on-chain operations on mainnet

[leighmcculloch]

What problem does your feature solve?

When using the CLI to perform on-chain operations (deploy, invoke, etc.) on mainnet, there's no confirmation step before the transaction is submitted. This means users could accidentally execute operations on mainnet when they intended to use testnet, or proceed with operations they didn't fully intend to run.

This is especially relevant as the CLI becomes more streamlined (e.g., auto-building before deploy as discussed in #2047), making it easier to perform on-chain operations with fewer commands.

What would you like to see?

Add an interactive confirmation prompt when any command is about to perform an on-chain operation on mainnet. The prompt could:

1. Display the network being used (e.g., "You are about to submit a transaction to mainnet")
2. Show relevant details about the operation
3. Ask for confirmation before proceeding

The prompt could be bypassed with a flag like --yes or -y for scripted/CI usage.

What alternatives are there?

• Status quo: No confirmation, users must be careful about which network they're targeting
• Environment-based safety: Require explicit --network mainnet flag rather than inferring from config (more friction)
• Dry-run by default: Require --execute flag to actually submit transactions (significant UX change)

Related: #2047 (discussion originated in comments)

[willemneal]

Honestly we should expand this to testnet as well since the goal is to act as a staging ground with similar workflows.

A testnet change would probably break more current workflows but a simple -y wouldn't be that much to add.