Implement Plonky3 `AirBuilder` main trace constraints code generation

In light of upcoming support for Plonk3, we should start implementing support for generating constraints using the [`AirBuilder`](https://github.com/Plonky3/Plonky3/blob/main/air/src/air.rs) interface. There are several examples in the plonky3 repository on how to implement it, such as [`keccak`](https://github.com/Plonky3/Plonky3/blob/main/keccak-air/src/air.rs).

We should focus on outputting the main trace constraints before handling bus constraints in the auxiliary trace, though these should be easy to support once the main ones are handled.

Study the Plonky3 repository's AirBuilder interface and the keccak-air example to understand how constraints are defined. The main trace constraints generation code needs to be added to air-script, likely in a module responsible for code generation. Start by examining existing constraint generation logic and map it to the AirBuilder methods. Verify the output by testing with a simple AIR program.

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