Make the toner forecast an order, not a table

The report answers a purchasing question, and it was answering it in seven
columns, two tables and a rowspan. What someone actually needs from it is a
short list of what to buy.

So it opens with that list, grouped by part number with a quantity. Two
cartridges of the same part in different printers is a quantity of two, which
is the number an order needs and the one a per-printer table made the reader
count by hand. It covers what is empty plus what goes within a fortnight -
ordering only what is already empty means running empty. There is a copy
button, because it ends up pasted into a mail.

Below it the cartridges sit in urgency bands rather than in one long list
sorted by a number. The question is which pile a thing is in, and a pile that
is empty is worth seeing as empty. Everything past "empty" starts collapsed;
the order list above already covers the same ground in a tenth of the height.

The row is a cartridge now, not a printer, so it can carry its own part number,
its own level bar and its own countdown. Nesting supplies under a printer meant
opening a printer to find out whether anything on it needed doing.

Cartridges with no part mapped are counted on a single line rather than given
one each. They cannot be dropped, since that would quietly shorten the order,
and they cannot be ordered from here either - the job they represent is
mapping them, which is one job however many there are.

Bands and the order horizon are decided server-side, next to the arithmetic
that produces them, so a heading cannot disagree with what got added to the
list.

Checked against a fleet of 43 dev printers with real part mappings, driven by
a stub Zabbix - live Zabbix is not reachable from the dev box.

CHANGELOG.md

@@ -77,6 +77,19 @@ that consumed it. The theme of the release is making those failures visible:
 each fix ships with the check, report or document that would have surfaced it.
 
 
+### Changed
+
+- The toner forecast is read as an order, not as a table. It opens with what to
+  buy - grouped by part number, with a quantity - because two cartridges of the
+  same part in different printers is a quantity of two, and that was a number
+  the reader had to work out by hand. Below it, cartridges sit in urgency bands
+  (empty / two weeks / thirty days / later) rather than in one long sortable
+  list, since the question being asked is which pile a thing is in. A row is
+  now a cartridge rather than a printer, carries its own part number and a
+  level bar, and everything past "empty" starts collapsed. Cartridges with no
+  part mapped are counted on one line instead of a line each: they still have
+  to be ordered, but not from this page - the job is to map them.
+
 ### Fixed
 
 - The toner forecast was reading the wrong end of the window. Zabbix applies a