Add the YOTA and OK/OM DX contests

Both are in the station's log and neither could be opened. The rules are
written from the published ones and checked by replaying the log.

YOTA scores a contact by the age the other operator sends: 13 points down to 10
for anyone 25 or under, whatever the continent, and 1 point or 3 for everyone
else. Every age worked on a band is a multiplier. The 2024, 2025 and 2026 logs
come out to the contact.

OK/OM DX is the first contest whose exchange differs by the other station's
country: a county from OK and OM stations, a serial number from everyone else,
in the two columns N1MM keeps them in, and `SkipsField` walks the entry window
past the box that does not apply. Points depend on which side the operator is
on, and Czechia and Slovakia count as the two countries they are. The 2023 log
comes out to the contact.

The Cabrillo exchange now gets the entry, because YOTA sends an age that only
the contest setup knows.

Two differences are left in the log, both from the .udc files the operator
used: their YOTA file only lists ages 7 to 25, so a younger operator scored as
an adult, and one OK/OM log was made with the file for stations outside OK and
OM while signing an OM call.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RoGtneMQaz4M9w7Kk49AVD

src/Nonemm.Contests/N1mmContestNames.cs

@@ -6,6 +6,11 @@ namespace Nonemm.Contests;
 /// never plain `CQWW`. Our registry is keyed by the family, so a log written by
 /// N1MM has to have its contest name turned back into a family and a mode
 /// before the rules can be built.
+///
+/// The `.udc` files people use for OK/OM DX name it per mode as well, and one
+/// file per side of the contest — `OKOMDXS_DX` is the one a station outside OK
+/// and OM runs. Both sides are the same rules here, so both names resolve to
+/// the same contest.
 public static class N1mmContestNames
 {
     private static readonly Dictionary<string, (string Family, ModeCategory Mode)> Known =
@@ -27,6 +32,10 @@ public static class N1mmContestNames
             ["NAQPCW"] = ("NAQP", ModeCategory.Cw),
             ["NAQPSSB"] = ("NAQP", ModeCategory.Phone),
             ["NAQPRTTY"] = ("NAQP", ModeCategory.Digital),
+            ["OKOMDXC"] = ("OKOMDX", ModeCategory.Cw),
+            ["OKOMDXS"] = ("OKOMDX", ModeCategory.Phone),
+            ["OKOMDXC_DX"] = ("OKOMDX", ModeCategory.Cw),
+            ["OKOMDXS_DX"] = ("OKOMDX", ModeCategory.Phone),
         };
 
     public static bool TryResolve(string name, out string family, out ModeCategory mode)