feat(httpapi): add local audit log with portal dual-write

Локальный audit_log (миграции pg/sqlite), GET /v1/audit, запись на CRUD и async push в auth-portal (source_app=bgp).

Co-authored-by: Cursor <[email protected]>

internal/store/backend.go

@@ -132,6 +132,11 @@ type Backend interface {
 	AppendRuntimeLogCleanupAudit(tenantID, actor, filename, action string, sizeBefore int64, sizeAfter *int64, detail map[string]any) (string, error)
 	ListRuntimeLogCleanupAudit(tenantID, cursor string, limit int) ([]*RuntimeLogCleanupAudit, string, bool, error)
 
+	// CRUD audit log (tenant-scoped; optional portal ingest push from httpapi).
+	AppendAudit(in AuditAppendInput) (*AuditEntry, error)
+	ListAudit(tenantID, cursor string, limit int, filter AuditListFilter) ([]*AuditEntry, string, bool, error)
+	MarkAuditPortalPushed(id string) error
+
 	// Firewall blocklist clients and policy rules.
 	ListFirewallClients(tenantID string) ([]*FirewallClient, error)
 	GetFirewallClient(tenantID, id string) (*FirewallClient, error)