[WIP] Modify README.md for developer workflow instructions

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

Role: You are a senior technical writer and common lisp developer
Task: Modify the README.md to:

1. Use the same format as https://github.com/Lisp-Stat/cl-jupyter-image/blob/master/README.md
2. Read the shell scripts at https://github.com/Symbolics/devcontainer-features/tree/master/src/ls-dev and rewrite the section on Developer Workflow using those script. I want you to pay particular attention to how a new developer will use the container to start developing. Document only the ls-init.sh script (https://raw.githubusercontent.com/Symbolics/devcontainer-features/refs/heads/master/src/ls-dev/ls-init.sh). Examine and understand the scripts contents so you can do this properly.

Task 2 above is critically important. Think through how a new user, inexperienced in Common Lisp, will need to approach the problem and do not assume he has any knowledge of Common Lisp. Especially expand:

1. The local docker run, giving various combinations using the ls-init.sh to pre-configure the container
2. Creating github forks and configuring the container so that he can become a contributor.

Review your work, update and continue to iterate as required. Ask clarification questions if you need to.

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