Tighten NPC interaction validation and consistency

internal/modules/dnd/shared/diagnostics/diagnostics.go

@@ -6,10 +6,13 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
 )
 
 const (
 	MaxIssues         = 20
+	MaxWarnings       = 20
 	MaxDisplayedRunes = 128
 	MaxMessageBytes   = 4096
 )
@@ -37,6 +40,28 @@ func Aggregate(prefix string, issues []string) string {
 	return aggregateMessage(prefix, displayed, len(issues)-len(displayed))
 }
 
+// LimitWarnings returns at most MaxWarnings warnings, reserving the final
+// position for a deterministic omission summary when truncation is required.
+func LimitWarnings(warnings []contracts.Warning, scope, reasonCode string) []contracts.Warning {
+	if warnings == nil {
+		return nil
+	}
+	if len(warnings) <= MaxWarnings {
+		bounded := make([]contracts.Warning, len(warnings))
+		copy(bounded, warnings)
+		return bounded
+	}
+	displayed := MaxWarnings - 1
+	bounded := make([]contracts.Warning, displayed, MaxWarnings)
+	copy(bounded, warnings[:displayed])
+	bounded = append(bounded, contracts.Warning{
+		Scope:      scope,
+		ReasonCode: reasonCode,
+		Message:    fmt.Sprintf("%d additional warning(s) omitted", len(warnings)-displayed),
+	})
+	return bounded
+}
+
 func aggregateMessage(prefix string, issues []string, omitted int) string {
 	message := prefix + ": " + strings.Join(issues, ", ")
 	if omitted > 0 {