refactor(decodes): real columns, spelled-out flags, bigger type

First pass on the panel from operating feedback.

Columns are a grid template shared by the header row and every data row, so
the two cannot drift and the eye has a rail to follow. It is capped at
1500 px and centred: free-flowing, a 2500 px window put the country a foot
from the callsign it belonged to and left a hole in the middle of every
line.

"New" gets a COLUMN. It was only a coloured edge before, which says
something is special without saying what — and every one of these is a
reason to break off what you are doing and call. The entity verdict is a
solid badge, the orthogonal ones (park, grid, prefix, county) are outlined
in the colours markerColour already gives the cluster list and the band
map, so a new park is the same green in all three. Applied inline because
those are categorical --chart-* custom properties, which the theme does not
expose as Tailwind colour utilities: written as border-chart-7 the badge
would simply have had no colour.

Band and mode selectors now appear only when the feed actually carries more
than one of each. One MSHV is one band and one mode, so for most operators
they were furniture; they show up the day a second instance puts a second
band on the link, which is the only day they mean anything. Same rule for
continent, and a receiver count when more than one instance is feeding.

Added a LoTW-only filter, and raised the type throughout (call and message
to 14 px, secondary to 12 px, badges to 11 px) with more room per row.

The decode payload now carries the sending application's own id. It tells
two receivers apart on one multicast group — and it is the address a
WSJT-X Reply message would have to go back to, so it is carried now rather
than requiring another trip through the parser later.

internal/integrations/udp/server.go

@@ -127,6 +127,12 @@ type Event struct {
 	DecodeTRPeriod int
 	DecodeDial     int64 // dial frequency the decode was heard on, for the band
 	DecodeOffAir   bool  // decoded from a file rather than off the air
+	// ProgramID is the sending application's own id ("WSJT-X", "MSHV", or
+	// "WSJT-X - 2" for a second instance started with --rig-name). It is what
+	// tells two receivers apart on one multicast group — and it is the address a
+	// Reply message would have to be sent back to, so it is carried even though
+	// nothing replies yet.
+	ProgramID string
 
 	// TxMessage is what the operator's digital app is sending, with Transmitting
 	// true while the carrier is actually up. From Status, so ~1 Hz.
@@ -439,6 +445,7 @@ func (s *Server) handle(pkt []byte, remote *net.UDPAddr) {
 			ev.DecodeTRPeriod = tr
 			ev.DecodeDial = dial
 			ev.DecodeOffAir = w.OffAir
+			ev.ProgramID = w.ProgramID
 			break
 		}
 		// Only a logged QSO is worth a line — WSJT-X/MSHV send a Status packet