feat(watchlist): exact match by default, * for a family

The prefix matching ported from DXHunter swallowed too much: a three-letter
special-event entry N8W lit up NEEDED for N8WCR, a different station entirely.
The implicit becomes explicit — a bare entry matches exactly that call, a
trailing star makes it a family: VK9* catches every VK9…, RI0SP* the
expedition's portable forms. A star anywhere else (or alone) is refused at Add
rather than silently matching nothing. Same rule in the backend Match and the
tab's own matcher, pinned by test.

internal/watchlist/watchlist_test.go

@@ -7,22 +7,36 @@ import (
 	"testing"
 )
 
-func TestPrefixMatch(t *testing.T) {
+func TestGlobMatch(t *testing.T) {
 	s := New(filepath.Join(t.TempDir(), "watchlist.json"))
-	if err := s.Add("RI0SP", false); err != nil {
+	if err := s.Add("RI0SP*", false); err != nil {
 		t.Fatal(err)
 	}
-	// The reason prefix matching exists: expeditions sign portable.
+	if err := s.Add("N8W", false); err != nil {
+		t.Fatal(err)
+	}
+	// A starred entry is a family: the expedition's portable forms.
 	for _, call := range []string{"RI0SP", "RI0SP/MM", "RI0SP/P"} {
 		if _, ok := s.Match(call); !ok {
 			t.Errorf("Match(%q) = false, want true", call)
 		}
 	}
-	if _, ok := s.Match("RI0S"); ok {
-		t.Error("a SHORTER call must not match the entry")
+	// A bare entry is THAT call — the reported bug was N8W lighting up for
+	// N8WCR, a different station entirely.
+	if _, ok := s.Match("N8W"); !ok {
+		t.Error("exact entry must match its own call")
 	}
-	if _, ok := s.Match("F4BPO"); ok {
-		t.Error("an unrelated call matched")
+	if _, ok := s.Match("N8WCR"); ok {
+		t.Error("exact entry must NOT match a longer call")
+	}
+	if _, ok := s.Match("RI0S"); ok {
+		t.Error("a SHORTER call must not match a starred entry")
+	}
+	if err := s.Add("VK*9", false); err == nil {
+		t.Error("a mid-string star must be refused")
+	}
+	if err := s.Add("*", false); err == nil {
+		t.Error("a bare star must be refused")
 	}
 }