Add output schema registry and public contract docs

internal/core/reporting/report.go

@@ -10,6 +10,7 @@ import (
 )
 
 type ProcessReport struct {
+	ReportMetadata               ReportMetadata       `json:"report_metadata"`
 	Phase                        string               `json:"phase"`
 	Status                       string               `json:"status"`
 	Operation                    string               `json:"operation"`
@@ -32,6 +33,18 @@ type ProcessReport struct {
 	ModuleResults                []ModuleReport       `json:"module_results,omitempty"`
 }
 
+const (
+	DefaultProcessReportSchemaName    = "audita-process-report"
+	DefaultProcessReportSchemaVersion = "v1"
+)
+
+type ReportMetadata struct {
+	ReportSchemaName    string `json:"report_schema_name"`
+	ReportSchemaVersion string `json:"report_schema_version"`
+	OutputSchema        string `json:"output_schema"`
+	ConfigVersion       *int   `json:"config_version,omitempty"`
+}
+
 type ModuleReport struct {
 	ModuleKey          string                    `json:"module_key"`
 	ModuleInstance     string                    `json:"module_instance"`