Log the time the BARTG exchange went out

The BARTG RTTY contest sends the time with the serial number, and both
stations log the time the other one sent. The entry window now has the
report, serial and time boxes N1MM's has, and the time this station sent
is stamped into the MiscText column as the exchange message goes out, or
at log time when nothing sent it. The Cabrillo line writes that time and
falls back to the time of the contact when the column is empty, which is
what N1MM writes, in N1MM's columns.

The total score was points times every multiplier. N1MM's class works
out points times the countries and areas together, times the continents.
Per-contact points and multiplier flags do not change, so the station's
2022 log still scores contact for contact as N1MM did.

N1MM has a class each for the March HF RTTY contest and the September
sprint. This program has one contest holding the March rules under the
sprint's name, and docs/unfinished.md now says so.

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

docs/unfinished.md

@@ -88,6 +88,13 @@ character away from the spotted one is looked up in the callsign database, which
 is a few hundred lookups per spot; two characters away is a few hundred thousand,
 which is too much work per spot for the little it would add.
 
+**Two BARTG contests share one set of rules.** N1MM has a class each for the
+March HF RTTY contest, `BARTGSRTTY`, and the September sprint, `BARTGRTTYS`.
+This program has one contest, named `BARTGRTTYS`, holding the March rules — the
+ones the station's log needs — and both of N1MM's names open a log with it. A
+sprint log would be scored by the wrong rules, and a log started here writes
+`BARTGRTTYS` into the contest name, which N1MM would read as the sprint.
+
 **Digital modes.** A contact can be logged as RTTY or another digital mode, and
 the contest rules score it, but there is no digital window: no decoding, no
 transmitting, no interface to fldigi, MMTTY or similar.
@@ -160,9 +167,6 @@ What still differs, and why:
   `MultWindowType` setting, and those lists are not held here, so a US state
   sent into an OK/OM DX log counts as a multiplier here and not in N1MM. Three
   contacts across the two logs.
-- **The BARTG Sprint** stores the time of the contact in the exchange column,
-  which N1MM fills in by itself. Nothing here fills it in yet, so a log written
-  here carries the serial number alone.
 
 ## Known rough edges