[MM-64686] Expose audit logging functionality via plugin API (#31204)

This commit exposes audit logging functionality to plugins via the plugin API, allowing plugins to create and log audit records. Additionally, it addresses a gob encoding issue that could cause plugin crashes when audit data contains nil pointers or unregistered types.

server/channels/audit/audit.go

@@ -6,9 +6,12 @@ package audit
 import (
 	"fmt"
 
+	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
 )
 
+const DefMaxQueueSize = 1000
+
 type Audit struct {
 	logger *mlog.Logger
 
@@ -30,14 +33,14 @@ func (a *Audit) Init(maxQueueSize int) {
 }
 
 // LogRecord emits an audit record with complete info.
-func (a *Audit) LogRecord(level mlog.Level, rec Record) {
+func (a *Audit) LogRecord(level mlog.Level, rec model.AuditRecord) {
 	flds := []mlog.Field{
-		mlog.String(KeyEventName, rec.EventName),
-		mlog.String(KeyStatus, rec.Status),
-		mlog.Any(KeyActor, rec.Actor),
-		mlog.Any(KeyEvent, rec.EventData),
-		mlog.Any(KeyMeta, rec.Meta),
-		mlog.Any(KeyError, rec.Error),
+		mlog.String(model.AuditKeyEventName, rec.EventName),
+		mlog.String(model.AuditKeyStatus, rec.Status),
+		mlog.Any(model.AuditKeyActor, rec.Actor),
+		mlog.Any(model.AuditKeyEvent, rec.EventData),
+		mlog.Any(model.AuditKeyMeta, rec.Meta),
+		mlog.Any(model.AuditKeyError, rec.Error),
 	}
 
 	a.logger.Log(level, "", flds...)