feat(CHAIN-3336): add Rust bindings and reorganize bindings directory

[xenoliss]

Replaces #200

Summary

Set up Rust contract bindings under bindings/rust/ as a standalone crate and remove the legacy Go bindings.

• Remove the old Go bindings under bindings/go/.
• Add the Rust bindings crate (base-contracts-bindings) under bindings/rust/.
• Generate Rust bindings for all contracts defined under src/ using forge bind.
• Use a single global regex matcher derived from src/**/*.sol filenames to restrict forge bind to source contracts only.

The Rust crate is set up so downstream Rust consumers can depend on it directly via Cargo without needing Foundry locally.

This PR also adds a just bindings-generate workflow that regenerates the committed Rust bindings from the current src/ contract set.

To keep the new Rust bindings reliable, this PR adds validation recipes and CI coverage:

• just bindings-check-no-build verifies that committed Rust bindings stay in sync with forge-artifacts by checking forge bind output without rewriting files.
• just bindings-check runs the same consistency check and then cargo check in bindings/rust to ensure the crate compiles.
• CI now installs Rust and runs just bindings-check.

[linear]

CHAIN-3336 Expose rust bindings from base/contracts

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1

[jackchuma]

Foundry actually provides a utility for this. This PR can basically be reduced to

  bindings-generate: build-source
    forge bind --select "..." --crate-name base-contracts-bindings -b bindings/rust --overwrite

  bindings-check:
    forge bind --select "..." --crate-name base-contracts-bindings -b bindings/rust --skip-build

https://www.getfoundry.sh/reference/forge/bind#forge-bind

[jackchuma]

I also think we should add bindings for all contracts under the src/ directory

[jackchuma]

Oh and I think we can remove the go bindings

Approved review 3960222222 from jackchuma is now dismissed due to new commit. Re-request for approval.