Add work function and band depth values to energy charts

[brettfiedler]

During an interview with a low vision consultant, we noted that there was no indication of where the work function or band depth were in the PDOM. This was deemed pedagogically problematic, as they are landmark energy values to compare the recorded photon/electron energies to.

[brettfiedler]

I tried having Claude implement this in a branch (features/photoelectric-effect/issues/271)

It adds two more bullet list items that disappear when their related marker checkbox is unchecked.

I had trouble mentally justifying a raw dump of the band depth value, and instead had it create a derived value that defined the bottom of the band relative to zero. We can't use the work function or fermi level as the reference for band depth, since they are not always available. Only zero is always there.

I am not sure if this is the best way to go! This might benefit from a quick checkin with TS to see if this is "good enough".

And then I am unsure of the implementation, of course.

[brettfiedler]

Perhaps I will assign to Marla to see if she has better ideas.

[marlitas]

I did some small cleanup to the code, but otherwise I actually think this wasn't a super invasive change. Seems good to me code wise. I'll let @brettfiedler close out if everything looks good.

[marlitas]

Oh actually, let me know if you want me to merge it in before you close it :-)