Fixed probe cleanup

- Offline probes share bounded directory rescans after concurrent file creation
- Cleanup preserves other I/O failures
- Symlink targets remain untouched
- Probe tests use Mockito to reproduce cleanup races and failure boundaries

probe/src/main/java/art/arcane/iris/probe/GenerationProbe.java

@@ -56,7 +56,6 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
-import java.util.stream.Stream;
 
 public final class GenerationProbe {
     private static final List<Throwable> REPORTED = Collections.synchronizedList(new ArrayList<>());
@@ -564,7 +563,7 @@ public final class GenerationProbe {
             }
         }
         try {
-            deleteRecursively(workRoot.toPath());
+            ProbeWorkspaceCleanup.deleteRecursively(workRoot.toPath());
         } catch (Throwable e) {
             failure = appendFailure(failure, e);
         }
@@ -581,19 +580,6 @@ public final class GenerationProbe {
         return failure;
     }
 
-    private static void deleteRecursively(Path root) throws Exception {
-        if (!Files.exists(root)) {
-            return;
-        }
-        List<Path> paths;
-        try (Stream<Path> walk = Files.walk(root)) {
-            paths = walk.sorted(Comparator.reverseOrder()).toList();
-        }
-        for (Path path : paths) {
-            Files.deleteIfExists(path);
-        }
-    }
-
     private static List<Throwable> settleAndDrain() throws InterruptedException {
         List<Throwable> drained = new ArrayList<>();
         long quietSince = System.currentTimeMillis();

probe/src/main/java/art/arcane/iris/probe/ProbeWorkspaceCleanup.java

@@ -0,0 +1,54 @@
+package art.arcane.iris.probe;
+
+import java.io.IOException;
+import java.nio.file.DirectoryNotEmptyException;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
+
+final class ProbeWorkspaceCleanup {
+    private static final int MAXIMUM_ATTEMPTS = 4;
+    private static final SimpleFileVisitor<Path> DELETE_VISITOR = new SimpleFileVisitor<>() {
+        @Override
+        public FileVisitResult visitFile(Path file, BasicFileAttributes attributes) throws IOException {
+            Files.deleteIfExists(file);
+            return FileVisitResult.CONTINUE;
+        }
+
+        @Override
+        public FileVisitResult visitFileFailed(Path file, IOException failure) throws IOException {
+            if (failure instanceof NoSuchFileException) {
+                return FileVisitResult.CONTINUE;
+            }
+            throw failure;
+        }
+
+        @Override
+        public FileVisitResult postVisitDirectory(Path directory, IOException failure) throws IOException {
+            if (failure != null) {
+                throw failure;
+            }
+            Files.deleteIfExists(directory);
+            return FileVisitResult.CONTINUE;
+        }
+    };
+
+    private ProbeWorkspaceCleanup() {
+    }
+
+    static void deleteRecursively(Path root) throws IOException {
+        for (int attempt = 1; ; attempt++) {
+            try {
+                Files.walkFileTree(root, DELETE_VISITOR);
+                return;
+            } catch (DirectoryNotEmptyException failure) {
+                if (attempt == MAXIMUM_ATTEMPTS) {
+                    throw failure;
+                }
+            }
+        }
+    }
+}

probe/src/main/java/art/arcane/iris/probe/RealPackProbeSupport.java

@@ -43,7 +43,6 @@ import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -56,7 +55,6 @@ import java.util.concurrent.ForkJoinTask;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.locks.LockSupport;
-import java.util.stream.Stream;
 
 final class RealPackProbeSupport {
     private static final List<Throwable> REPORTED = Collections.synchronizedList(new ArrayList<>());
@@ -616,7 +614,7 @@ final class RealPackProbeSupport {
             if (clone.waitFor() == 0) {
                 return destination;
             }
-            deleteRecursively(destination.toPath());
+            ProbeWorkspaceCleanup.deleteRecursively(destination.toPath());
         }
         Path sourcePath = source.toPath();
         Files.walkFileTree(sourcePath, EnumSet.of(FileVisitOption.FOLLOW_LINKS), Integer.MAX_VALUE,
@@ -657,26 +655,13 @@ final class RealPackProbeSupport {
 
     private static Throwable deleteWorkRoot(File workRoot) {
         try {
-            deleteRecursively(workRoot.toPath());
+            ProbeWorkspaceCleanup.deleteRecursively(workRoot.toPath());
             return null;
         } catch (Throwable failure) {
             return failure;
         }
     }
 
-    private static void deleteRecursively(Path root) throws Exception {
-        if (!Files.exists(root)) {
-            return;
-        }
-        List<Path> paths;
-        try (Stream<Path> walk = Files.walk(root)) {
-            paths = walk.sorted(Comparator.reverseOrder()).toList();
-        }
-        for (Path path : paths) {
-            Files.deleteIfExists(path);
-        }
-    }
-
     private static Throwable appendFailure(Throwable failure, Throwable additional) {
         if (failure == null) {
             return additional;