fix(hamlog): read the site's own confirmation field, not a guessed one

A real record from their export settles it:

	<CALL:4>RL6M … <CNTY:5>RO-19 <APP_HAMLOG_R150COUNTRY:6>Russia
	<APP_HAMLOG_QSO_CFM:1>Y

The confirmation lives in APP_HAMLOG_QSO_CFM. The four names guessed before a
file was available — APP_HAMLOG_QSL and friends — were all wrong, which is the
argument for reading one rather than reasoning about it.

So that becomes the canonical key everywhere: the award source, the row colours,
the grid column and the bulk editor. Importing a log downloaded from HAMLOG now
carries its confirmations into OpsLog with nothing to rename. The older names,
including the APP_OPSLOG_HAMLOG_QSL that OpsLog itself wrote in the meantime,
are still honoured on read so nothing already stamped stops counting.

internal/qso/bulkmode_test.go

@@ -33,7 +33,9 @@ func TestHamlogFieldsAreBulkEditable(t *testing.T) {
 	for field, want := range map[string]string{
 		"hamlog_sent":      "APP_OPSLOG_HAMLOG_SENT",
 		"hamlog_sent_date": "APP_OPSLOG_HAMLOG_SENT_DATE",
-		"hamlog_rcvd":      "APP_OPSLOG_HAMLOG_QSL",
+		// Their field name — see award.HamlogQSLKey. Editing it by hand and
+		// importing their ADIF must land in the SAME place.
+		"hamlog_rcvd":      "APP_HAMLOG_QSO_CFM",
 		"hamlog_rcvd_date": "APP_OPSLOG_HAMLOG_QSL_DATE",
 	} {
 		if got := BulkExtraKey(field); got != want {