Phase A: generierter Dart-Client + DI-Foundation für Rust-Backend

OpenAPI-Generator-Setup:
- tool/generate_api_client.sh: Direkter Aufruf der openapi-generator-cli.jar
  (Java-CLI statt Dart-build_runner-Integration — vermeidet die
  analyzer-/source_gen-Version-Hölle mit json_serializable)
- tool/fetch_openapi_generator.sh: lädt die JAR (29 MB) nach (gitignored)
- openapi/holzleitner.json: Snapshot der Backend-Spec für reproduzierbare
  Generation
- packages/holzleitner_api/: generiertes Dart-Sub-Package (built_value +
  dio), per path-dep im Haupt-pubspec eingehängt

Netzwerk-Layer (lib/data/network/):
- BackendConfig: API- und Keycloak-Endpoints für Local-Dev (localhost
  wegen Keycloak-iss-Claim).
- AuthTokenProvider-Schnittstelle.
- DevPasswordGrantTokenProvider: Phase-A-Provider via Keycloak
  password-grant, Token-Caching mit Expiry-Check (Phase B ersetzt das
  durch flutter_appauth PKCE).
- HolzleitnerAuthInterceptor: dynamischer Bearer-Inject pro Request.
- HolzleitnerApiFactory: baut die generierte HolzleitnerApi-Klasse
  mit unserem Interceptor statt der vier Default-Auth-Interceptors.
- network_locator.registerNetworking(): get_it-Setup, in main() vor
  runApp() aufgerufen.

Clean-Arch-Scaffolding (lib/data/, lib/domain/):
- Verzeichnisstruktur für Phase C+D angelegt (mapper/, repository/,
  entity/, repository/) — befüllt sich in den Folge-Phasen.

Smoke-Test:
- tool/smoke_test_api.dart ruft /health (ungeschützt) und /me/cars
  (mit Bearer) via generiertem Client — grün gegen lokales Backend.

packages/holzleitner_api/lib/src/model/scan_event.g.dart

@@ -0,0 +1,158 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'scan_event.dart';
+
+// **************************************************************************
+// BuiltValueGenerator
+// **************************************************************************
+
+class _$ScanEvent extends ScanEvent {
+  @override
+  final AuditAction action;
+  @override
+  final String? actorCarId;
+  @override
+  final String clientScanId;
+  @override
+  final DateTime clientScannedAt;
+  @override
+  final String deliveryItemId;
+  @override
+  final String? reason;
+
+  factory _$ScanEvent([void Function(ScanEventBuilder)? updates]) =>
+      (ScanEventBuilder()..update(updates))._build();
+
+  _$ScanEvent._(
+      {required this.action,
+      this.actorCarId,
+      required this.clientScanId,
+      required this.clientScannedAt,
+      required this.deliveryItemId,
+      this.reason})
+      : super._();
+  @override
+  ScanEvent rebuild(void Function(ScanEventBuilder) updates) =>
+      (toBuilder()..update(updates)).build();
+
+  @override
+  ScanEventBuilder toBuilder() => ScanEventBuilder()..replace(this);
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(other, this)) return true;
+    return other is ScanEvent &&
+        action == other.action &&
+        actorCarId == other.actorCarId &&
+        clientScanId == other.clientScanId &&
+        clientScannedAt == other.clientScannedAt &&
+        deliveryItemId == other.deliveryItemId &&
+        reason == other.reason;
+  }
+
+  @override
+  int get hashCode {
+    var _$hash = 0;
+    _$hash = $jc(_$hash, action.hashCode);
+    _$hash = $jc(_$hash, actorCarId.hashCode);
+    _$hash = $jc(_$hash, clientScanId.hashCode);
+    _$hash = $jc(_$hash, clientScannedAt.hashCode);
+    _$hash = $jc(_$hash, deliveryItemId.hashCode);
+    _$hash = $jc(_$hash, reason.hashCode);
+    _$hash = $jf(_$hash);
+    return _$hash;
+  }
+
+  @override
+  String toString() {
+    return (newBuiltValueToStringHelper(r'ScanEvent')
+          ..add('action', action)
+          ..add('actorCarId', actorCarId)
+          ..add('clientScanId', clientScanId)
+          ..add('clientScannedAt', clientScannedAt)
+          ..add('deliveryItemId', deliveryItemId)
+          ..add('reason', reason))
+        .toString();
+  }
+}
+
+class ScanEventBuilder implements Builder<ScanEvent, ScanEventBuilder> {
+  _$ScanEvent? _$v;
+
+  AuditAction? _action;
+  AuditAction? get action => _$this._action;
+  set action(AuditAction? action) => _$this._action = action;
+
+  String? _actorCarId;
+  String? get actorCarId => _$this._actorCarId;
+  set actorCarId(String? actorCarId) => _$this._actorCarId = actorCarId;
+
+  String? _clientScanId;
+  String? get clientScanId => _$this._clientScanId;
+  set clientScanId(String? clientScanId) => _$this._clientScanId = clientScanId;
+
+  DateTime? _clientScannedAt;
+  DateTime? get clientScannedAt => _$this._clientScannedAt;
+  set clientScannedAt(DateTime? clientScannedAt) =>
+      _$this._clientScannedAt = clientScannedAt;
+
+  String? _deliveryItemId;
+  String? get deliveryItemId => _$this._deliveryItemId;
+  set deliveryItemId(String? deliveryItemId) =>
+      _$this._deliveryItemId = deliveryItemId;
+
+  String? _reason;
+  String? get reason => _$this._reason;
+  set reason(String? reason) => _$this._reason = reason;
+
+  ScanEventBuilder() {
+    ScanEvent._defaults(this);
+  }
+
+  ScanEventBuilder get _$this {
+    final $v = _$v;
+    if ($v != null) {
+      _action = $v.action;
+      _actorCarId = $v.actorCarId;
+      _clientScanId = $v.clientScanId;
+      _clientScannedAt = $v.clientScannedAt;
+      _deliveryItemId = $v.deliveryItemId;
+      _reason = $v.reason;
+      _$v = null;
+    }
+    return this;
+  }
+
+  @override
+  void replace(ScanEvent other) {
+    _$v = other as _$ScanEvent;
+  }
+
+  @override
+  void update(void Function(ScanEventBuilder)? updates) {
+    if (updates != null) updates(this);
+  }
+
+  @override
+  ScanEvent build() => _build();
+
+  _$ScanEvent _build() {
+    final _$result = _$v ??
+        _$ScanEvent._(
+          action: BuiltValueNullFieldError.checkNotNull(
+              action, r'ScanEvent', 'action'),
+          actorCarId: actorCarId,
+          clientScanId: BuiltValueNullFieldError.checkNotNull(
+              clientScanId, r'ScanEvent', 'clientScanId'),
+          clientScannedAt: BuiltValueNullFieldError.checkNotNull(
+              clientScannedAt, r'ScanEvent', 'clientScannedAt'),
+          deliveryItemId: BuiltValueNullFieldError.checkNotNull(
+              deliveryItemId, r'ScanEvent', 'deliveryItemId'),
+          reason: reason,
+        );
+    replace(_$result);
+    return _$result;
+  }
+}
+
+// ignore_for_file: deprecated_member_use_from_same_package,type=lint