docs: add project state markers guide (state diagram + taxonomy)

[neel212p]

What

Add a short Practitioner Guide: a project state diagram (Mermaid stateDiagram-v2) and a compact taxonomy that describes common open-source project lifecycle states.

Why

This addresses issue #165 — it provides a simple visual and textual guide to help users decide whether to use, contribute to, adopt, or fork a project based on its state.

What I changed

• Added practitioner-guides/project-state-diagram.md containing:
  • The stateDiagram-v2 Mermaid diagram from the issue proposal
  • A short taxonomy table with recommended actions

Notes for reviewers

• Mermaid stateDiagram-v2 is used so the diagram renders on GitHub. If you'd prefer an SVG or a different location, I can update the PR.
• This is intentionally small to keep review friction low.

Closes #165

[neel212p]

Hi maintainers 👋
I’ve added the Practitioner Guide for project state markers and linked it to issue #165.
All checks have passed.
Could someone please review and approve when you have time?
Happy to make any changes if needed. Thank you!

[geekygirldawn]

Hi @neel212p! While we appreciate your contribution, practitioner guides are designed to be quite detailed and offer advice to practitioners. As such, they are usually done as a collaboration among people with a significant amount of experience working in open source and we have a process for doing this. I'd be happy to talk more about this if you're interested, but the guides take a very significant amount of time to write. You can see the other examples here: https://chaoss.community/about-chaoss-practitioner-guides/

Before we go any further, I'd be curious to learn more about your motivations and why you are interested in contributing here?