Update views and docs to handle new `TAX CALC` value for `asmt.procname`

[jeancochrane]

We learned from our data stakeholder about a new procname TAX CALC in asmt. My original question:

I just noticed that Oak Park 2025 PINs all seem to have a row in ASMT with procname "TAX CALC". What does this procname mean? Is it new?

Their reply:

That was a “stamp” placed by TR [the Treasurer] for their 2025 1st installment calculation; they are not picking up any values at all from the ladder (1st installment is ALWAYS 55% of the prior year total), but according to Tyler is needed to be in place. [...] It is my understanding that they will always have to run their tax bill calc job, which will generically stamp the system with TAXCALC. Its really just a generic tax calc job, which they use to “determine” tax bill amounts, whether its for adjusted EAVs for COEs and other tax bill adjustments.

We should investigate this field, document it, and make sure we're handling it properly in our views that consume asmt.procname.