Clarified ingest target errors

- Rejected target pack names outside letters, digits, underscores and hyphens before ingest starts
- Reported an existing target pack with a translated replace=true hint instead of the raw path

adapters/modded-common/src/main/java/art/arcane/iris/modded/command/ModIngestArguments.java

@@ -29,6 +29,7 @@ import java.util.regex.Pattern;
 record ModIngestArguments(String sourcePack, String targetPack, String dimension, Set<String> namespaces, boolean replace) {
     static final List<String> OPTION_SUGGESTIONS = List.of("dimension=", "namespaces=", "replace=true");
     private static final Pattern PACK = Pattern.compile("[A-Za-z0-9_.-]+");
+    private static final Pattern TARGET_PACK = Pattern.compile("[A-Za-z0-9_-]+");
     private static final Pattern DIMENSION = Pattern.compile("[A-Za-z0-9_/.-]+");
     private static final Pattern NAMESPACE = Pattern.compile("[a-z0-9_.-]+");
     private static final String DIMENSION_KEY = "dimension";
@@ -76,6 +77,9 @@ record ModIngestArguments(String sourcePack, String targetPack, String dimension
         }
         requirePack(source);
         requirePack(target);
+        if (!TARGET_PACK.matcher(target).matches()) {
+            throw new IllegalArgumentException("invalid target pack name '" + target + "'");
+        }
         if (source.equals(target)) {
             throw new IllegalArgumentException("source and target must be different packs");
         }

adapters/modded-common/src/main/java/art/arcane/iris/modded/command/ModdedCatalogCommands.java

@@ -43,6 +43,7 @@ import com.mojang.brigadier.suggestion.SuggestionsBuilder;
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
@@ -211,6 +212,9 @@ final class ModdedCatalogCommands {
         try {
             ModIngestReport report = ModIngester.ingest(request);
             source.execute(() -> reportIngest(source, report));
+        } catch (FileAlreadyExistsException exists) {
+            source.execute(() -> IrisModdedCommands.fail(source, IrisLanguage.plain(ModdedCatalogMessages.INGEST_TARGET_EXISTS,
+                    MessageArgument.untrusted("target", request.targetPack().getFileName().toString()))));
         } catch (IOException | RuntimeException failure) {
             ModdedIrisLog.error("Iris mod ingest into " + request.targetPack() + " failed", failure);
             String reason = reason(failure);

adapters/modded-common/src/main/java/art/arcane/iris/modded/localization/ModdedCatalogMessages.java

@@ -91,6 +91,10 @@ public final class ModdedCatalogMessages {
             "iris.modded.catalog.ingest_failed",
             "Mod ingest failed: {reason}"
     );
+    public static final TextKey INGEST_TARGET_EXISTS = TextKey.of(
+            "iris.modded.catalog.ingest_target_exists",
+            "Target pack '{target}' already exists. Add replace=true to overwrite it."
+    );
     public static final TextKey INGEST_LINE = TextKey.of(
             "iris.modded.catalog.ingest_line",
             "  {summary}"
@@ -129,6 +133,7 @@ public final class ModdedCatalogMessages {
             INGEST_PACK_MISSING,
             INGEST_STARTED,
             INGEST_FAILED,
+            INGEST_TARGET_EXISTS,
             INGEST_LINE,
             INGEST_COMPLETE,
             HELP_CATALOG,