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.

pubspec.lock

@@ -249,6 +249,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.7.11"
+  dio:
+    dependency: "direct main"
+    description:
+      name: dio
+      sha256: aff32c08f92787a557dd5c0145ac91536481831a01b4648136373cddb0e64f8c
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.9.2"
+  dio_web_adapter:
+    dependency: transitive
+    description:
+      name: dio_web_adapter
+      sha256: "2f9e64323a7c3c7ef69567d5c800424a11f8337b8b228bad02524c9fb3c1f340"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.2"
   easy_stepper:
     dependency: "direct main"
     description:
@@ -488,6 +504,13 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.0"
+  holzleitner_api:
+    dependency: "direct main"
+    description:
+      path: "packages/holzleitner_api"
+      relative: true
+    source: path
+    version: "1.0.0"
   http:
     dependency: "direct main"
     description:
@@ -712,6 +735,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.0"
+  one_of:
+    dependency: transitive
+    description:
+      name: one_of
+      sha256: "25fe0fcf181e761c6fcd604caf9d5fdf952321be17584ba81c72c06bdaa511f0"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.0"
+  one_of_serializer:
+    dependency: transitive
+    description:
+      name: one_of_serializer
+      sha256: "3f3dfb5c1578ba3afef1cb47fcc49e585e797af3f2b6c2cc7ed90aad0c5e7b83"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.0"
   package_config:
     dependency: transitive
     description:
@@ -864,6 +903,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.5.0"
+  quiver:
+    dependency: transitive
+    description:
+      name: quiver
+      sha256: ea0b925899e64ecdfbf9c7becb60d5b50e706ade44a85b2363be2a22d88117d2
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.2.2"
   rxdart:
     dependency: "direct main"
     description: