Add JSON validation middleware to ensure valid API responses

- Created JSONValidationMiddleware that validates all JSON responses
- Ensures that even on timeout or internal errors, a valid JSON error response is returned
- Applied to all API endpoints including /status.json
- Prevents client-side JSON parse errors when server encounters issues

internal/database/database.go

@@ -1482,6 +1482,7 @@ func (d *Database) GetASPeersContext(ctx context.Context, asn int) ([]ASPeer, er
 		err := rows.Scan(&peer.ASN, &peer.Handle, &peer.Description, &peer.FirstSeen, &peer.LastSeen)
 		if err != nil {
 			d.logger.Error("Failed to scan peer row", "error", err, "asn", asn)
+
 			continue
 		}
 		peers = append(peers, peer)