Added modded worldgen catalog

- Captured the worldgen catalog after server start, scanning registries on the server thread and encoding and writing on a worker into config/irisworldgen/catalog/worldgen-catalog.json
- Added WorldgenCatalogFingerprint over namespace versions and registry keys
- Added /iris catalog [namespace|refresh] and /iris ingest mods <source> <target> with keyed dimension, namespaces and replace options
- Added catalog messages and help entries for every shipped locale
- Added tests for catalog assembly, namespace summaries, ingest arguments, the registry scan and command registration

core/src/test/java/art/arcane/iris/pack/ingest/catalog/WorldgenCatalogFingerprintTest.java

@@ -0,0 +1,77 @@
+/*
+ * Iris is a World Generator for Minecraft Servers
+ * Copyright (c) 2026 Arcane Arts (Volmit Software)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package art.arcane.iris.pack.ingest.catalog;
+
+import org.junit.Test;
+
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+public class WorldgenCatalogFingerprintTest {
+    private static final List<CatalogNamespace> NAMESPACES = List.of(
+            new CatalogNamespace("minecraft", "Minecraft", "26.3"),
+            new CatalogNamespace("examplemod", "Example Mod", "1.0.0"));
+
+    @Test
+    public void fingerprintIsLowercaseSha256Hex() {
+        String fingerprint = WorldgenCatalogFingerprint.of(NAMESPACES, Map.of("biome", List.of("minecraft:plains")));
+
+        assertEquals(64, fingerprint.length());
+        assertTrue(fingerprint.matches("[0-9a-f]{64}"));
+    }
+
+    @Test
+    public void fingerprintIgnoresNamespaceAndKeyOrder() {
+        String ordered = WorldgenCatalogFingerprint.of(NAMESPACES, Map.of(
+                "biome", List.of("examplemod:glade", "minecraft:plains"),
+                "placed_feature", List.of("examplemod:ore_glimmer", "minecraft:ore_iron")));
+        String shuffled = WorldgenCatalogFingerprint.of(List.of(NAMESPACES.get(1), NAMESPACES.get(0)), Map.of(
+                "placed_feature", List.of("minecraft:ore_iron", "examplemod:ore_glimmer"),
+                "biome", List.of("minecraft:plains", "examplemod:glade")));
+
+        assertEquals(ordered, shuffled);
+    }
+
+    @Test
+    public void fingerprintChangesWithModVersion() {
+        Map<String, List<String>> keys = Map.of("biome", List.of("examplemod:glade"));
+        String original = WorldgenCatalogFingerprint.of(NAMESPACES, keys);
+        String updated = WorldgenCatalogFingerprint.of(List.of(NAMESPACES.get(0),
+                new CatalogNamespace("examplemod", "Example Mod", "1.0.1")), keys);
+
+        assertNotEquals(original, updated);
+    }
+
+    @Test
+    public void fingerprintChangesWhenAKeyIsAddedOrMovesRegistry() {
+        String original = WorldgenCatalogFingerprint.of(NAMESPACES, Map.of(
+                "biome", List.of("examplemod:glade"), "structure", List.of()));
+        String added = WorldgenCatalogFingerprint.of(NAMESPACES, Map.of(
+                "biome", List.of("examplemod:glade", "examplemod:marsh"), "structure", List.of()));
+        String moved = WorldgenCatalogFingerprint.of(NAMESPACES, Map.of(
+                "biome", List.of(), "structure", List.of("examplemod:glade")));
+
+        assertNotEquals(original, added);
+        assertNotEquals(original, moved);
+    }
+}