Paint the band the way N1MM paints it

Behind the bandmap scale, the CW part of the band is one shade and the phone
part another, with a third for a digital block. That is what N1MM's graphical
bandmap does: ResizeBandPanels puts a CW, a Digi and an SSB panel behind the
scale, sized from its CWBands, DigiBands and SSBBands tables. Anything past a
band edge is shaded red, which is the only place the edges themselves show, and
it only appears now that the slice can reach past an edge.

The defaults are N1MM's: CW ends at 1840, 3600, 7125, 14150 and so on, and the
digital pair is empty until somebody fills it in, exactly as N1MM ships. They
are one worldwide set rather than one per ITU region, which is also N1MM's
answer — the reason recorded for leaving this out, that the segments differ by
region, was wrong about what N1MM holds. 60M and everything above 2M get no
entry, because N1MM's own numbers there contradict themselves: its 1.25M CW top
is below its phone start, and its 70CM CW top is above the band.

Config ▸ Sub bands edits them, one row per band in kilohertz, with a Defaults
button. Only the rows that differ are written to the settings file, so a plan
nobody has touched leaves nothing behind. BandPlan is an object rather than a
static table, so the stored changes layer over the defaults and the bandmap
picks up a save without a restart.

The numbers are a drawing aid, not a licence. Nothing stops a contact being
logged either side of a boundary.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/unfinished.md

@@ -45,10 +45,6 @@ data. The file is read without them.
 the contest rules score it, but there is no digital window: no decoding, no
 transmitting, no interface to fldigi, MMTTY or similar.
 
-**Band-plan colouring of the bandmap scale.** N1MM colours the scale by CW,
-digital and phone segment. The segments differ by ITU region and there is no
-band-plan table here, so it is left out rather than guessed.
-
 **Contest coverage.** Eight contests are built in, plus whatever `.udc` files
 are in the user-defined folder. N1MM ships well over a hundred. Opening a log
 from a contest not in the registry fails with the contest name, which is the
@@ -64,6 +60,12 @@ thread, and `AppSession.TakeFromNetwork` reopens the whole contest to do it.
 That is correct but heavy, and it discards what is typed in an entry window on
 another radio.
 
+**The band plan covers 160M to 2M only.** 60M and everything above 2M get no
+CW, digital or phone shading on the bandmap, because N1MM's own numbers for
+those bands contradict themselves — its CW top for 1.25M is below its phone
+start, and its 70CM CW top is above the band. Config ▸ Sub bands cannot add a
+band that has no default.
+
 **Available mults and Qs is only as good as the bandmap.** It lists what is
 spotted, so a multiplier nobody has spotted is not there. N1MM's window also
 shows the mults a contest has and nobody has worked, which needs a list of every