feat(fls): DNS records from /dns/hosts, as Java's server answers them

Java's DNS server reads its records from the text file /dns/hosts on every
query. dnsHosts.ts ports that reading (DNSServer.leseRecordListe,
ResourceRecord, Dateisystem.holeDatei) and keeps in the model the records
Java answers: type exactly A, MX or NS, and a name Java accepted. The file
stays in the file system as it is.

Both oracles read 76 hand-picked hosts files (dns-hosts.cases.txt): the
Java oracle through DNSServer.holeResourceRecords (DnsHostsCases), the
Swift oracle through TopologyDNSHostsFileCodec (--dns-hosts). The Java view
matches Java on every case; the model matches Swift except for 33 named
cases in twelve reasons: Java splits at single spaces and LF only, has no
comments or "IN", turns a TTL that is no int into 3600, keeps duplicates,
and empties names with a leading digit. The Swift dump now carries each
server's records; the corpus comparison covers them on 16 files.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/core/src/runtime/config.ts

@@ -180,10 +180,25 @@ export interface GnutellaConfiguration {
   readonly maximumKnownPeers: number;
 }
 
-/** The DNS records follow with the hosts file (Java's /dns/hosts). */
+export type DnsRecordType = 'A' | 'MX' | 'NS';
+
+/**
+ * One record a DNS server answers with (Swift's TopologyDNSResourceRecord):
+ * `name` in lower case without the final dot (the root is "."), `target` an
+ * IPv4 address for A, an absolute name ("mail.filius.de.") for MX and NS.
+ */
+export interface DnsResourceRecord {
+  readonly name: string;
+  readonly type: DnsRecordType;
+  readonly ttlSeconds: number;
+  readonly target: string;
+}
+
 export interface DnsServerConfiguration {
   readonly recursiveResolutionEnabled: boolean;
   readonly forwardingServerIPAddress?: string;
+  /** In the order of Java's /dns/hosts, which stays in the file system as it is. */
+  readonly records: readonly DnsResourceRecord[];
 }
 
 /**