refactor: harden diagnostics and consolidate runtime code

audit/internal/webui/tasks_test.go

@@ -227,6 +227,29 @@ func TestTaskArtifactsDirStartsWithTaskNumber(t *testing.T) {
 	}
 }
 
+func TestFinalizeTaskArtifactPathsKeepsSourceWhenDestinationExists(t *testing.T) {
+	logsDir := t.TempDir()
+	sourceDir := filepath.Join(logsDir, "running-artifacts")
+	if err := os.Mkdir(sourceDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+	task := &Task{ID: "TASK-007", Name: "NVIDIA Benchmark", Status: TaskDone, ArtifactsDir: sourceDir}
+	destinationDir := taskArtifactsDir(logsDir, task, TaskDone)
+	if err := os.Mkdir(destinationDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	q := &taskQueue{logsDir: logsDir}
+	q.finalizeTaskArtifactPathsLocked(task)
+
+	if task.ArtifactsDir != sourceDir {
+		t.Fatalf("artifacts dir = %q, want retained source %q after destination collision", task.ArtifactsDir, sourceDir)
+	}
+	if task.ReportJSONPath != filepath.Join(sourceDir, "report.json") {
+		t.Fatalf("report path = %q, want source directory", task.ReportJSONPath)
+	}
+}
+
 func TestHandleAPITasksStreamReplaysPersistedLogWithoutLiveJob(t *testing.T) {
 	dir := t.TempDir()
 	logPath := filepath.Join(dir, "task.log")