refactor(benchmarks): unify benchmark structure, enable CLI parameterization, run matrix, add CSV/JSON/pretty output

- All benchmarks now use a unified base mixin for setup/teardown (BenchmarkWithScope).
- Added args package support: CLI flags for choosing benchmarks, chain counts, nesting depths, output format.
- Support for running benchmarks in matrix mode (multiple parameter sets).
- Machine-readable output: csv, json, pretty-table.
- Loop and naming lint fixes, unused imports removed.

benchmark_cherrypick/lib/benchmark_utils.dart

@@ -0,0 +1,29 @@
+import 'package:cherrypick/cherrypick.dart';
+
+/// Миксин для упрощения работы с CherryPick Scope в бенчмарках.
+mixin BenchmarkWithScope {
+  Scope? _scope;
+
+  /// Отключить глобальные проверки циклов и создать корневой scope с модулями.
+  void setupScope(List<Module> modules,
+      {bool disableCycleDetection = true,
+      bool disableCrossScopeCycleDetection = true}) {
+    if (disableCycleDetection) {
+      CherryPick.disableGlobalCycleDetection();
+    }
+    if (disableCrossScopeCycleDetection) {
+      CherryPick.disableGlobalCrossScopeCycleDetection();
+    }
+    _scope = CherryPick.openRootScope();
+    _scope!.installModules(modules);
+  }
+
+  /// Закрывает текущий scope.
+  void teardownScope() {
+    CherryPick.closeRootScope();
+    _scope = null;
+  }
+
+  /// Получить текущий scope. Не null после setupScope.
+  Scope get scope => _scope!;
+}