fix: add Ouroboros Genesis support for Cardano Node 10.5.1+ (#637)

Implement support for Cardano Node 10.5.1 which uses Ouroboros Genesis consensus protocol.
This replaces bootstrap peers with big ledger peer snapshots for better decentralization.

Changes:
- Add PeerSnapshotService to load peers from Genesis peer snapshot files
- Create model classes for BigLedgerPool, PeerSnapshotConfig, and Relay
- Update TopologyConfigServiceImpl to use peer snapshots with bootstrap fallback
- Add support for domain, IPv4, IPv6, and address relay formats
- Update mainnet, preprod, and preview topology.json to use peer-snapshot.json
- Add comprehensive unit tests (16 test cases) using mainnet peer snapshot
- Keep devkit with bootstrap peers for backward compatibility

The implementation maintains dynamic peer discovery priority:
1. Try dynamically discovered peers from yaci-indexer (when enabled)
2. Fallback to static peers from peer-snapshot.json (Genesis mode)
3. Fallback to bootstrap peers (legacy mode)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Mateusz Czeladka <mateusz.czeladka@cardanofoundation.org>
Co-authored-by: Claude <noreply@anthropic.com>

Author: 3 people

api/src/main/java/org/cardanofoundation/rosetta/api/network/service/PeerSnapshotServiceImpl.java

@@ -14,7 +14,6 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -26,12 +25,6 @@
 @Slf4j
 public class PeerSnapshotServiceImpl implements PeerSnapshotService {
 
-  /**
-   * Maximum number of peers to return. This limit prevents returning excessive peer lists
-   * and ensures randomization of peer selection rather than always returning the same peers.
-   */
-  private static final int MAX_PEERS = 25;
-
   @Override
   public List<Peer> loadPeersFromSnapshot(@NotNull String peerSnapshotFile, @NotNull String baseDirectory) {
     try {
@@ -77,19 +70,10 @@ private PeerSnapshotConfig parsePeerSnapshot(String snapshotFilePath) throws IOE
   }
 
   private List<Peer> extractPeersFromSnapshot(PeerSnapshotConfig peerSnapshot) {
-    List<Peer> allPeers = peerSnapshot.getBigLedgerPools().stream()
+    return peerSnapshot.getBigLedgerPools().stream()
         .flatMap(pool -> pool.getRelays().stream())
         .map(this::mapRelayToPeer)
         .toList();
-
-    // Shuffle to randomize peer selection and limit to MAX_PEERS
-    // This ensures we don't always return the same peers
-    List<Peer> shuffledPeers = new ArrayList<>(allPeers);
-    Collections.shuffle(shuffledPeers);
-
-    return shuffledPeers.stream()
-        .limit(MAX_PEERS)
-        .toList();
   }
 
   @NotNull

api/src/test/java/org/cardanofoundation/rosetta/api/network/service/PeerSnapshotServiceImplTest.java

@@ -36,8 +36,7 @@ void shouldLoadPeersFromMainnetSnapshot() {
       // then
       assertNotNull(peers);
       assertThat(peers).isNotEmpty();
-      assertThat(peers.size()).isLessThanOrEqualTo(25); // Limited to MAX_PEERS (25)
-      assertThat(peers.size()).isEqualTo(25); // Should have exactly 25 peers if snapshot has enough
+      assertThat(peers.size()).isGreaterThan(100); // Mainnet has many big ledger pools
     }
 
     @Test
@@ -57,18 +56,11 @@ void shouldExtractDomainRelaysCorrectly() {
           })
           .toList();
 
-      // Due to randomization, we can't guarantee specific domains are present
-      // Just verify that domain peers exist and have correct format
       assertThat(domainPeers).isNotEmpty();
 
-      domainPeers.forEach(peer -> {
-        // Domain peers should have format address:port
-        assertThat(peer.getPeerId()).contains(":");
-
-        // Metadata should indicate domain type
-        Map<String, Object> metadata = (Map<String, Object>) peer.getMetadata();
-        assertThat(metadata.get("type")).isEqualTo("domain");
-      });
+      // Verify at least one known domain relay
+      assertThat(domainPeers)
+          .anyMatch(peer -> peer.getPeerId().contains("cardano.figment.io"));
     }
 
     @Test
@@ -190,19 +182,13 @@ void shouldExtractMultipleRelaysFromSinglePool() {
       List<Peer> peers = peerSnapshotService.loadPeersFromSnapshot(peerSnapshotFile, baseDirectory);
 
       // then
-      // Due to randomization, we can't guarantee specific pools are in the selection
-      // Verify we have peers limited to MAX_PEERS
-      assertThat(peers).hasSizeLessThanOrEqualTo(25);
-      assertThat(peers).isNotEmpty();
-
-      // Verify all peers have valid format (address:port)
-      peers.forEach(peer -> {
-        assertThat(peer.getPeerId()).contains(":");
+      // Nordic pool has multiple relays (Relay1-6.NordicPool.org)
+      List<Peer> nordicPoolRelays = peers.stream()
+          .filter(peer -> peer.getPeerId().contains("NordicPool.org"))
+          .toList();
 
-        // All peers should have metadata with type
-        Map<String, Object> metadata = (Map<String, Object>) peer.getMetadata();
-        assertThat(metadata).containsKey("type");
-      });
+      assertThat(nordicPoolRelays).isNotEmpty();
+      assertThat(nordicPoolRelays.size()).isGreaterThan(1);
     }
 
     @Test
@@ -230,20 +216,15 @@ void shouldVerifyKnownMainnetRelays() {
       List<Peer> peers = peerSnapshotService.loadPeersFromSnapshot(peerSnapshotFile, baseDirectory);
 
       // then
-      // Due to randomization, we can't guarantee specific relays are present
-      // Instead verify that all peers have valid format and metadata
-      assertThat(peers).isNotEmpty();
-      assertThat(peers.size()).isEqualTo(25);
-
-      peers.forEach(peer -> {
-        // All peers should have a peer ID with port
-        assertThat(peer.getPeerId()).contains(":");
+      List<String> peerIds = peers.stream()
+          .map(Peer::getPeerId)
+          .toList();
 
-        // All peers should have metadata with type
-        Map<String, Object> metadata = (Map<String, Object>) peer.getMetadata();
-        assertThat(metadata).containsKey("type");
-        assertThat(metadata.get("type")).isIn("domain", "IPv4", "IPv6");
-      });
+      // Verify some known mainnet relays exist
+      assertThat(peerIds)
+          .anyMatch(id -> id.contains("cardano.figment.io"))
+          .anyMatch(id -> id.contains("NordicPool.org"))
+          .anyMatch(id -> id.contains("cardanosuisse.com"));
     }
 
     @Test
@@ -256,9 +237,9 @@ void shouldExtractAllRelaysFromAllPools() {
       List<Peer> peers = peerSnapshotService.loadPeersFromSnapshot(peerSnapshotFile, baseDirectory);
 
       // then
-      // Peers are now limited to MAX_PEERS (25) and randomized
-      assertThat(peers.size()).isLessThanOrEqualTo(25);
-      assertThat(peers.size()).isEqualTo(25); // Should have exactly 25 peers
+      // Mainnet snapshot has many pools with multiple relays each
+      // Total should be significantly higher than the number of pools
+      assertThat(peers.size()).isGreaterThan(200);
     }
 
     @Test
@@ -309,31 +290,5 @@ void shouldVerifyCommonPorts() {
       assertThat(ports)
           .contains("3001", "6000");
     }
-
-    @Test
-    void shouldRandomizePeerSelection() {
-      // given
-      String peerSnapshotFile = "peer-snapshot.json";
-      String baseDirectory = "../config/node/mainnet";
-
-      // when - load peers multiple times
-      List<Peer> firstLoad = peerSnapshotService.loadPeersFromSnapshot(peerSnapshotFile, baseDirectory);
-      List<Peer> secondLoad = peerSnapshotService.loadPeersFromSnapshot(peerSnapshotFile, baseDirectory);
-
-      // then - both should have 25 peers
-      assertThat(firstLoad.size()).isEqualTo(25);
-      assertThat(secondLoad.size()).isEqualTo(25);
-
-      // And they should be different due to randomization (very high probability)
-      // We check if at least 5 peers are different in order
-      long differentPeers = 0;
-      for (int i = 0; i < Math.min(firstLoad.size(), secondLoad.size()); i++) {
-        if (!firstLoad.get(i).getPeerId().equals(secondLoad.get(i).getPeerId())) {
-          differentPeers++;
-        }
-      }
-
-      assertThat(differentPeers).isGreaterThan(5);
-    }
   }
 }