feat(worked): fold portable callsigns into the worked-before history

Typing RK3DWA found nothing while RK3DWA/3 found 21 QSOs, so a station's
history was only visible if you happened to type the exact form it had been
logged under — and an operator who worked it as /0, /P or /MM saw none of it.
The other RDA tools and Log4OM fold these together; this does too.

The predicate strips the suffix from what was typed and matches "call = base OR
call LIKE base/%", so it works from either end: the base call finds the portable
QSOs and a portable call finds the plain ones. Deliberately not a bare prefix
LIKE 'RK3DWA%', which would also match RK3DWAB — a different station. The '/' is
what makes it the same operator.

Settings -> General to turn it off. Default ON, hence the inverted storage: an
existing install has no key, and reading that as OFF would leave everyone with
the behaviour we were asked to change.

Contest dupe checking is untouched — it runs through ContestDupe, a separate
binding, and stays an exact match as a contest requires.

internal/qso/qso.go

@@ -1585,11 +1585,35 @@ type BandMode struct {
 // rendering a recent-contacts mini-list.
 const maxWorkedEntries = 50
 
+// callMatch builds the WHERE fragment that selects one station's QSOs.
+//
+// Exact by default. With variants on, an operator's portable forms count as the
+// same station: RK3DWA, RK3DWA/3, RK3DWA/P and RK3DWA/QRP are one person, and
+// someone asking "have I worked RK3DWA?" means the person, not the string.
+// Typing 21 QSOs' worth of history only when you happen to add "/3" is the
+// behaviour this replaces. The suffix is stripped from what was TYPED too, so
+// it matches both ways round — RK3DWA/3 also finds the plain RK3DWA contacts.
+//
+// Deliberately NOT a bare "starts with": LIKE 'RK3DWA%' would also drag in
+// RK3DWAB, which is a different station. The '/' is what makes it the same one.
+func callMatch(call string, variants bool) (string, []any) {
+	if !variants {
+		return "callsign = ?", []any{call}
+	}
+	base := call
+	if i := strings.IndexByte(base, '/'); i > 0 {
+		base = base[:i]
+	}
+	return "(callsign = ? OR callsign LIKE ?)", []any{base, base + "/%"}
+}
+
 // WorkedBefore returns aggregated history at both callsign and DXCC level.
 // dxccHint lets the caller pass a known DXCC number (e.g. from a fresh QRZ
 // lookup) when the call has never been worked. If 0, the DXCC is inferred
 // from the most recent prior QSO with the same callsign.
-func (r *Repo) WorkedBefore(ctx context.Context, callsign string, dxccHint int) (WorkedBefore, error) {
+//
+// matchVariants folds the portable forms of the call together — see callMatch.
+func (r *Repo) WorkedBefore(ctx context.Context, callsign string, dxccHint int, matchVariants bool) (WorkedBefore, error) {
 	wb := WorkedBefore{
 		Callsign:      upperTrim(callsign),
 		Bands:         []string{},
@@ -1605,17 +1629,18 @@ func (r *Repo) WorkedBefore(ctx context.Context, callsign string, dxccHint int)
 	}
 
 	// ---- Per-callsign stats ----
+	pred, predArgs := callMatch(wb.Callsign, matchVariants)
 	if err := r.db.QueryRowContext(ctx,
-		`SELECT COUNT(*) FROM qso WHERE callsign = ?`, wb.Callsign).Scan(&wb.Count); err != nil {
+		`SELECT COUNT(*) FROM qso WHERE `+pred, predArgs...).Scan(&wb.Count); err != nil {
 		return wb, fmt.Errorf("count worked: %w", err)
 	}
 	if wb.Count > 0 {
 		// Pull the full QSO records (same columns as the Recent QSOs list) so
 		// the Worked-before grid can offer the same rich column picker.
 		rows, err := r.db.QueryContext(ctx, `SELECT `+selectCols+`
-            FROM qso WHERE callsign = ?
+            FROM qso WHERE `+pred+`
             ORDER BY qso_date DESC, id DESC
-            LIMIT ?`, wb.Callsign, maxWorkedEntries)
+            LIMIT ?`, append(append([]any{}, predArgs...), maxWorkedEntries)...)
 		if err != nil {
 			return wb, fmt.Errorf("query worked: %w", err)
 		}
@@ -1648,7 +1673,7 @@ func (r *Repo) WorkedBefore(ctx context.Context, callsign string, dxccHint int)
 		if wb.Count > maxWorkedEntries {
 			var firstStr sql.NullString
 			_ = r.db.QueryRowContext(ctx,
-				`SELECT MIN(qso_date) FROM qso WHERE callsign = ?`, wb.Callsign).Scan(&firstStr)
+				`SELECT MIN(qso_date) FROM qso WHERE `+pred, predArgs...).Scan(&firstStr)
 			if firstStr.Valid {
 				wb.First = parseTimeLoose(firstStr.String)
 			}
@@ -1673,8 +1698,8 @@ func (r *Repo) WorkedBefore(ctx context.Context, callsign string, dxccHint int)
 		var d sql.NullInt64
 		_ = r.db.QueryRowContext(ctx, `
             SELECT dxcc FROM qso
-            WHERE callsign = ? AND dxcc IS NOT NULL
-            ORDER BY qso_date DESC LIMIT 1`, wb.Callsign).Scan(&d)
+            WHERE `+pred+` AND dxcc IS NOT NULL
+            ORDER BY qso_date DESC LIMIT 1`, predArgs...).Scan(&d)
 		if d.Valid {
 			dxcc = int(d.Int64)
 		}