Pre working step #227

	name: TS Lint and Typecheck

	on: [push]

	jobs:
	lint-and-typecheck:
	name: Lint and Typecheck
	runs-on: ubuntu-latest
	environment: CI
	steps:
	- name: Checkout Repository
	uses: actions/checkout@v4

	- name: Use Node.js 20.x
	uses: actions/setup-node@v3
	with:
	node-version: '20.x'

	- name: Enable Corepack and Install Yarn 4
	run: \|
	corepack enable
	yarn set version latest

	- name: Install Dependencies
	run: yarn install

	- name: Run TypeScript Linter
	run: yarn lint:all

	# We don't store circuit and smart contract compilation artefacts in the repo,
	# but typecheck fails on import without them so we just create fake files here
	- name: Create fake circuit compilation artefacts
	working-directory: .
	run: \|
	mkdir -p target
	touch target/main.json

	- name: Create fake smart contract build artefacts
	working-directory: .
	run: \|
	mkdir -p ethereum_history_api/contracts/out/UltraVerifier.sol
	echo '{ "abi": [], "bytecode": { "object": "" } }' > ethereum_history_api/contracts/out/UltraVerifier.sol/UltraVerifier.json

	- name: Run TypeScript Typecheck
	run: yarn typecheck:all

	- name: Run TypeScript format check
	run: yarn format:all:ci

Provide feedback