Derive report-period SPC convective outlooks

internal/briefing/modules.go

@@ -185,6 +185,8 @@ func derivedFactAvailable(requirement module.FactRequirement, ctx ModuleContext)
 		return len(ctx.Derived.DaypartSummaries) > 0
 	case module.RequiresDerivedPrecipTiming:
 		return true
+	case module.RequiresDerivedSPCConvectiveOutlooks:
+		return ctx.Derived.SPCConvectiveOutlooks != nil
 	default:
 		return false
 	}