Refine the descripton design process.

[pixelzoom]

For https://github.com/phetsims/special-ops/issues/269 ...

As noted in https://github.com/phetsims/special-ops/issues/270#issuecomment-2427942533 ...

• Work on the description design process is needed.
  Greenhouse had a very elaborate specification for description, and many iterations. For each iteration, it was difficult to identify which parts had been completed, which parts had changed, etc. For every dev team that @pixelzoom spoke with, the design process was entirely different. Consider process definition, design templates, design constraints, postmortems to identify what works and what needs improvement, ...