fix: CW decoder was loosing first caracters

internal/cwdecode/cwdecode_test.go

@@ -118,6 +118,26 @@ func TestDecodeWithQRM(t *testing.T) {
 	}
 }
 
+func TestDecodeFirstCharStrong(t *testing.T) {
+	const fs = 16000
+	var sb strings.Builder
+	d := New(fs, func(s string) { sb.WriteString(s) }, nil)
+	// Strong signal: the very first element (T = a dash) must not be eaten by
+	// lock acquisition. Output should begin with the first character.
+	samples := keyMessageAmp("TEST DE", fs, 20, 700, 16000)
+	for i := 0; i < len(samples); i += 200 {
+		end := i + 200
+		if end > len(samples) {
+			end = len(samples)
+		}
+		d.Process(samples[i:end])
+	}
+	got := strings.ToUpper(strings.TrimSpace(sb.String()))
+	if !strings.HasPrefix(got, "TEST") {
+		t.Fatalf("first chars lost on a strong signal: decoded %q, want it to start with TEST", got)
+	}
+}
+
 func TestDecodeNumbersAndProsign(t *testing.T) {
 	const fs = 16000
 	var sb strings.Builder