chore(`library`): make it easy to use Foundry's logic currently contained in `bin` in libraries

[odyslam]

Component

Forge

Describe the feature you would like

We are building tooling for a different use-case, but reusing a lot of Foundry's mental models for a superb DevEx. We are currently forking Forge for the following two reasons and I would really prefer if we didn't:

We want to be able to package forge as part of our tooling, but to do that we need a lot of the functionality that lives inside the bin of commands such as forge test/build. Moving them to their own crate would enable us to use them without needing to fork.

• chore: refactor forge for library use #10117
• chore: refactor cast for library use #10123
• chore: refactor anvil for library use #10139
• chore: refactor chisel for library use #10142

[zerosnacks]

Hi @odyslam

Splitting this feature request out into two parts to make it actionable:

1. Restructure existing crates to have a thin binary, moving all commands, opts and args into the src. This should make it easy to pick and mix for your use. Starting with Forge here, other binaries to follow: chore: refactor forge for library use #10117

2. Created a standalone ticket for extending cheatcodes here: feat(cheatcodes): create the ability to easily extend Foundry's cheatcodes using Reth's ext pattern #10118