ci: add GitHub Actions workflow to run tests on every PR and push

[Copilot]

• Investigate CI failure logs
• Fix: add apt-get install zsh step — tests use zsh -n for syntax checking but zsh is not pre-installed on ubuntu-latest

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[ChangeHow]

@copilot read errors from github actions and trying to update the action config to solve them.

[Copilot]

@copilot read errors from github actions and trying to update the action config to solve them.

Fixed in commit 0dc631f. The failures were caused by two tests (configs.test.js and verify.test.js) that run zsh -n for syntax checking — zsh isn't pre-installed on ubuntu-latest. Added sudo apt-get update && sudo apt-get install -y zsh as a step before npm ci.