Write implementation-notes.md

[AgustinVallejo]

Related to #93

JB already did some work and I will continue.

[marlitas]

Review Comments Part 1:

• I'm assuming you meant to link to the Quantum design doc instead?

* [Models of the Hydrogen Atom HTML5](https://docs.google.com/document/d/1fZT_vDD8sX8nkSpTxHOyoP6-XrAIJYo44dacLIbZO14/edit?pli=1&tab=t.0) (Parts of this are likely to be stale.)

• The Bloch Sphere section could use a bit more context and explanation. Mostly
  • I am unsure what is important for me to track because of the code and what pedagogically important. Perhaps it's both, but as a developer and/or maintainer I'm more interested in the former.
  • In AbstractBlochSphere you have the sentence They are related but will be linked in the implementations. I don't understand what is related and how it will be linked. That sentence is providing more confusion than clarity. If it's not important I would suggest to leave it out.
  • I would replace Same as above with Same as BlochSphereNode for clarity. That also doesn't lock you into that exact list order in case you add or change something.

[jbphet]

@AgustinVallejo - I've taken a shot at the initial version of this document, see https://github.com/phetsims/quantum-measurement/blob/main/doc/implementation-notes.md. I tagged you at two places (search for "Agustin") for parts that I think you might want to enhance. Also, the comments from @marlitas above are mostly about a Bloch sphere section that I copied and pasted from your Slack doc, so you can probably best address those. Assigning to you for next steps.

[AgustinVallejo]

I did some improvements on the documentation.

I am unsure what is important for me to track because of the code and what pedagogically important

Perhaps we can talk on monday so this is clearer among us and in the docs.

[marlitas]

I'm going to do one last pass tomorrow before signing off.

[marlitas]

Did you mean to say disseminated here?
These collections are created at startup but populated and decimated during the sim

[marlitas]

Done. Over to @AgustinVallejo and @jbphet!

[AgustinVallejo]

Thanks Marla!! Closing now