Remove Foundry NPM package and switch to local installation

[igorroncevic]

Summary

• remove Foundry npm packages from dev dependencies and lockfile
• run Foundry commands from the local PATH instead of npm-provided binaries
• install Foundry v1.7.0 in the shared CI setup action and document local v1.7.0 setup
• remove direct Foundry passthrough recipes from just

Test Plan

• forge --version
• pnpm --dir dev install --lockfile-only --offline
• just build
• just lint
• just test
• uv sync --project dev --locked
• just slither
• just coverage-check

[igorroncevic]

PR in template repo: cowprotocol/contracts-template#26

[gemini-code-assist]

Code Review

This pull request migrates the project from using local npm-wrapped Foundry binaries to the official Foundry toolchain by removing the @foundry-rs dependencies and updating the Justfile and CI configuration. Feedback indicates that the version v1.7.0 specified in the GitHub Action and README is incorrect, as it refers to the deprecated npm wrapper versioning rather than valid official Foundry release tags. The documentation and CI setup need to be updated with a correct version or commit hash to prevent installation failures.

[anxolin]

Sorry, im a bit lot on the motivation of this PR. I believe could provide more context

In the past you did one to install it using NPM , and cause NPM is still a dependency seemed a nice way to ensure we all use the same version.

Not saying is wrong, but i didn't get the motivation, plus the reason the README now has some commands in they lifecicle using just and some use forge