Fix zero UUID and storage metrics issues\n\n- Add ID generation in signAndCreateCommand to prevent zero UUIDs\n- Fix storage metrics metadata field (remove pq.Array)\n- Add IdempotencyKey field to AgentCommand model\n\nThese issues were causing duplicate key violations and storage page errors.

aggregator-server/internal/models/command.go

@@ -16,6 +16,7 @@ type AgentCommand struct {
 	Status         string     `json:"status" db:"status"`
 	Source         string     `json:"source" db:"source"`
 	Signature      string     `json:"signature,omitempty" db:"signature"`
+	IdempotencyKey *string    `json:"idempotency_key,omitempty" db:"idempotency_key"`
 	CreatedAt      time.Time  `json:"created_at" db:"created_at"`
 	UpdatedAt      time.Time  `json:"updated_at" db:"updated_at"`
 	SentAt         *time.Time `json:"sent_at,omitempty" db:"sent_at"`