Finalize SPC outlook feature addition and clean up implemented roadmap documentation

internal/normalizers/spc/convective_outlook_test.go

@@ -99,6 +99,9 @@ func TestConvectiveOutlookNormalizerProducesCanonicalSchemaAndMapsSample(t *test
 	if !strings.Contains(got.Discussion, "...DISCUSSION...") {
 		t.Fatalf("Discussion missing product text: %q", got.Discussion)
 	}
+	if !strings.HasPrefix(got.Discussion, "SPC AC 111234") {
+		t.Fatalf("Discussion = %q, want SPC product code prefix", got.Discussion)
+	}
 	if got.ID != "spc-convective-day1-categorical-slgt-2026-06-11T12:34:56Z-2026-06-11T13:00:00Z-0" {
 		t.Fatalf("ID = %q", got.ID)
 	}