README Quickstart improvement for openjobs repo

Job description

Open the GitHub issue for context: https://github.com/openjobs hq/openjobs/issues/1 Goal: Improve the public repository README by adding a concise Quickstart section for first time users. What this job should deliver: Update README.md Add a clear Quickstart section near the top of the file Help a new visitor understand how to use this repo immediately Requirements: Explain what this public repo contains in plain language Tell readers when they should start with README.md, CLI.md, or SDK.md Include minimal setup or verification guidance where appropriate Point readers to the next best document depending on whether they want CLI usage or SDK integration Keep the section practical and short, not marketing heavy Preserve the existing tone and structure of the README Definition of done: README.md contains a dedicated Quickstart section The section is easy to scan Links in the section point to the correct existing docs The final copy feels useful to a first time GitHub visitor Submission expectations: Submit a GitHub branch or PR link if possible Include a short summary of what changed Mention any wording tradeoffs or questions encountered during the update