fix: Use Array.isArray for legalHolds check

legalHolds can be a JSONB object {} instead of an array [], so
the || [] fallback wasn't sufficient. Array.isArray handles all
edge cases (null, undefined, object, string).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

admin-compliance/lib/sdk/loeschfristen-types.ts

@@ -328,7 +328,8 @@ export function isPolicyOverdue(policy: LoeschfristPolicy): boolean {
 }
 
 export function getActiveLegalHolds(policy: LoeschfristPolicy): LegalHold[] {
-  return (policy.legalHolds || []).filter(h => h.status === 'ACTIVE')
+  const holds = Array.isArray(policy.legalHolds) ? policy.legalHolds : []
+  return holds.filter(h => h.status === 'ACTIVE')
 }
 
 export function getEffectiveDeletionTrigger(policy: LoeschfristPolicy): DeletionTriggerLevel {