Dev container fixes and updates

[RembrandtK]

Fixes and updates:

• removing unneeded shared network dependency
• documentation updates
• remove duplicated git signing message
• do not install hardhat (global install not a good idea)
• install cloc and a script to use it to count Solidity code changes relative to main
• ignore forge-artifacts

scripts/count-changes not about dev container but useful script.

Everything else relates just to dev container configuration.

[Copilot]

Pull Request Overview

This PR updates the dev container configuration and supporting scripts, removing unused dependencies and enhancing documentation. Key changes include:

• A new script (scripts/count-changes) to count Solidity code changes using cloc.
• Removal of the shared network dependency and duplicate Git SSH signing message in the dev container settings.
• Updates to the Dockerfile to remove global Hardhat installation and install only the necessary packages.

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
scripts/count-changes	Adds a script for counting Solidity code changes using cloc.
packages/issuance/lib/forge-std	Adds a submodule commit reference for the forge-std library.
.devcontainer/project-setup.sh	Removes a duplicate Git SSH signing message to avoid redundancy.
.devcontainer/docker-compose.yml	Removes the unneeded shared network configuration.
.devcontainer/README.md	Updates documentation for clarity regarding container usage.
.devcontainer/Dockerfile	Eliminates global Hardhat installation; now installs ethers and cloc.